diff --git a/flex-config/attributes.lua b/flex-config/attributes.lua
index c39dd6132..3e61ad626 100644
--- a/flex-config/attributes.lua
+++ b/flex-config/attributes.lua
@@ -1,10 +1,9 @@
 -- This config example file is released into the Public Domain.
 
 -- This config shows how to access the attributes of OSM objects: the version,
--- changeset id, timestamp, user id and user name. For this to work the
--- command line option --extra-attributes/-x must be set, otherwise those
--- fields will be empty. Also note that some OSM files do not contain all
--- of those attributes, so check your input data if you get empty fields.
+-- changeset id, timestamp, user id and user name. Note that some OSM files do
+-- not contain all of those attributes, so check your input data if you get
+-- empty fields.
 
 -- Set this to the projection you want to use
 local srid = 4326
diff --git a/flex-config/bbox.lua b/flex-config/bbox.lua
index 920772859..3c9093b74 100644
--- a/flex-config/bbox.lua
+++ b/flex-config/bbox.lua
@@ -30,17 +30,6 @@ tables.boundaries = osm2pgsql.define_relation_table('boundaries', {
     { column = 'geom', type = 'multilinestring' },
 })
 
--- Helper function to remove some of the tags we usually are not interested in.
--- Returns true if there are no tags left.
-local function clean_tags(tags)
-    tags.odbl = nil
-    tags.created_by = nil
-    tags.source = nil
-    tags['source:ref'] = nil
-
-    return next(tags) == nil
-end
-
 -- Helper function that looks at the tags and decides if this is possibly
 -- an area.
 local function has_area_tags(tags)
@@ -91,10 +80,6 @@ local function format_bbox(object)
 end
 
 function osm2pgsql.process_node(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     tables.pois:insert({
         tags = object.tags,
         bbox = format_bbox(object),
@@ -103,10 +88,6 @@ function osm2pgsql.process_node(object)
 end
 
 function osm2pgsql.process_way(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     -- A closed way that also has the right tags for an area is a polygon.
     if object.is_closed and has_area_tags(object.tags) then
         tables.polygons:insert({
@@ -124,10 +105,6 @@ function osm2pgsql.process_way(object)
 end
 
 function osm2pgsql.process_relation(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     local relation_type = object:grab_tag('type')
 
     -- Store boundary relations as multilinestrings
diff --git a/flex-config/data-types.lua b/flex-config/data-types.lua
index d480e9145..082e0a18f 100644
--- a/flex-config/data-types.lua
+++ b/flex-config/data-types.lua
@@ -5,31 +5,33 @@
 -- at this file. This file demonstrates some column data type options.
 
 local highways = osm2pgsql.define_way_table('highways', {
-    { column = 'name',     type = 'text' },
+    { column = 'name', type = 'text' },
     -- We always need a highway type, so we can declare the column as NOT NULL
-    { column = 'type',     type = 'text', not_null = true },
+    { column = 'type', type = 'text', not_null = true },
 
     -- Add a SERIAL column and tell osm2pgsql not to fill it (PostgreSQL will
     -- do that for us)
-    { column = 'id',       sql_type = 'serial', create_only = true },
+    { column = 'id', sql_type = 'serial', create_only = true },
 
     -- type "direction" is special, see below
-    { column = 'oneway',   type = 'direction' },
+    { column = 'oneway', type = 'direction' },
     { column = 'maxspeed', type = 'int' },
 
     -- type "bool" is special, see below
-    { column = 'lit',      type = 'bool' },
-    { column = 'tags',     type = 'jsonb' }, -- also available: 'json', 'hstore'
+    { column = 'lit', type = 'bool' },
+    { column = 'tags', type = 'jsonb' }, -- also available: 'json', 'hstore'
 
     -- osm2pgsql doesn't know about PostgreSQL arrays, so we define the SQL
     -- type of this column and then have to convert our array data into a
     -- valid text representation for that type, see below.
-    { column = 'nodes',    sql_type = 'int8[]' },
-    { column = 'geom',     type = 'linestring' },
+    { column = 'nodes', sql_type = 'int8[]' },
+    { column = 'geom', type = 'linestring' },
 })
 
 -- Helper function to remove some of the tags we usually are not interested in.
--- Returns true if there are no tags left.
+-- Something like this can be useful if you are writing all tags to the
+-- database in a JSON(B) column and don't want that cluttered with lots of tags
+-- nobody cares about. Returns true if there are no tags left.
 local function clean_tags(tags)
     tags.odbl = nil
     tags.created_by = nil
diff --git a/flex-config/expire.lua b/flex-config/expire.lua
index 8a905c383..9912e3faa 100644
--- a/flex-config/expire.lua
+++ b/flex-config/expire.lua
@@ -45,7 +45,9 @@ tables.pois = osm2pgsql.define_node_table('pois', {
     -- Zero, one or more expire outputs are referenced in an `expire` field in
     -- the definition of any geometry column using the Web Mercator (3857)
     -- projection.
-    { column = 'geom', type = 'point', not_null = true, expire = { { output = expire_outputs.pois } } },
+    { column = 'geom', type = 'point', not_null = true, expire = {
+        { output = expire_outputs.pois }
+    }},
 })
 
 tables.lines = osm2pgsql.define_way_table('lines', {
diff --git a/flex-config/geometries.lua b/flex-config/geometries.lua
index b9a8f5e79..46741eea2 100644
--- a/flex-config/geometries.lua
+++ b/flex-config/geometries.lua
@@ -55,17 +55,6 @@ tables.pubs = osm2pgsql.define_node_table('pubs', {
     { column = 'name', type = 'text' }
 })
 
--- Helper function to remove some of the tags we usually are not interested in.
--- Returns true if there are no tags left.
-local function clean_tags(tags)
-    tags.odbl = nil
-    tags.created_by = nil
-    tags.source = nil
-    tags['source:ref'] = nil
-
-    return next(tags) == nil
-end
-
 -- Helper function that looks at the tags and decides if this is possibly
 -- an area.
 local function has_area_tags(tags)
@@ -105,10 +94,6 @@ local function has_area_tags(tags)
 end
 
 function osm2pgsql.process_node(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     local geom = object:as_point()
 
     tables.pois:insert({
@@ -124,10 +109,6 @@ function osm2pgsql.process_node(object)
 end
 
 function osm2pgsql.process_way(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     -- A closed way that also has the right tags for an area is a polygon.
     if object.is_closed and has_area_tags(object.tags) then
         -- Creating the polygon geometry takes time, so we do it once here
@@ -166,10 +147,6 @@ function osm2pgsql.process_way(object)
 end
 
 function osm2pgsql.process_relation(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     local relation_type = object:grab_tag('type')
 
     -- Store boundary relations as multilinestrings
diff --git a/flex-config/public-transport.lua b/flex-config/public-transport.lua
index a0b97539a..65c665e80 100644
--- a/flex-config/public-transport.lua
+++ b/flex-config/public-transport.lua
@@ -20,25 +20,25 @@
 local tables = {}
 
 tables.stops = osm2pgsql.define_node_table('stops', {
-    { column = 'tags',     type = 'jsonb' },
+    { column = 'tags', type = 'jsonb' },
     { column = 'rel_refs', type = 'text' }, -- for the refs from the relations
-    { column = 'rel_ids',  sql_type = 'int8[]' }, -- array with integers (for relation IDs)
-    { column = 'geom',     type = 'point', not_null = true },
+    { column = 'rel_ids', sql_type = 'int8[]' }, -- array with integers (for relation IDs)
+    { column = 'geom', type = 'point', not_null = true },
 })
 
 tables.lines = osm2pgsql.define_way_table('lines', {
-    { column = 'tags',     type = 'jsonb' },
+    { column = 'tags', type = 'jsonb' },
     { column = 'rel_refs', type = 'text' }, -- for the refs from the relations
-    { column = 'rel_ids',  sql_type = 'int8[]' }, -- array with integers (for relation IDs)
-    { column = 'geom',     type = 'linestring', not_null = true },
+    { column = 'rel_ids', sql_type = 'int8[]' }, -- array with integers (for relation IDs)
+    { column = 'geom', type = 'linestring', not_null = true },
 })
 
 -- Tables don't have to have a geometry column
 tables.routes = osm2pgsql.define_relation_table('routes', {
-    { column = 'ref',  type = 'text' },
+    { column = 'ref', type = 'text' },
     { column = 'type', type = 'text' },
     { column = 'from', type = 'text' },
-    { column = 'to',   type = 'text' },
+    { column = 'to', type = 'text' },
     { column = 'tags', type = 'jsonb' },
 })
 
@@ -46,9 +46,9 @@ tables.routes = osm2pgsql.define_relation_table('routes', {
 -- stop. We model them here by adding a center point as geometry plus the
 -- radius of a circle that contains everything in that stop.
 tables.stop_areas = osm2pgsql.define_relation_table('stop_areas', {
-    { column = 'tags',   type = 'jsonb' },
+    { column = 'tags', type = 'jsonb' },
     { column = 'radius', type = 'real', not_null = true },
-    { column = 'geom',   type = 'point', not_null = true },
+    { column = 'geom', type = 'point', not_null = true },
 })
 
 -- This will be used to store information about relations queryable by member
@@ -61,15 +61,6 @@ tables.stop_areas = osm2pgsql.define_relation_table('stop_areas', {
 local n2r = {}
 local w2r = {}
 
-local function clean_tags(tags)
-    tags.odbl = nil
-    tags.created_by = nil
-    tags.source = nil
-    tags['source:ref'] = nil
-
-    return next(tags) == nil
-end
-
 local function unique_array(array)
     local result = {}
 
@@ -128,8 +119,6 @@ function osm2pgsql.process_way(object)
         return
     end
 
-    clean_tags(object.tags)
-
     -- Data we will store in the 'lines' table always has the tags from
     -- the way
     local row = {
diff --git a/flex-config/route-relations.lua b/flex-config/route-relations.lua
index 245a5d6ff..a93101252 100644
--- a/flex-config/route-relations.lua
+++ b/flex-config/route-relations.lua
@@ -12,10 +12,10 @@
 local tables = {}
 
 tables.highways = osm2pgsql.define_way_table('highways', {
-    { column = 'tags',     type = 'jsonb' },
+    { column = 'tags', type = 'jsonb' },
     { column = 'rel_refs', type = 'text' }, -- for the refs from the relations
-    { column = 'rel_ids',  sql_type = 'int8[]' }, -- array with integers (for relation IDs)
-    { column = 'geom',     type = 'linestring', not_null = true },
+    { column = 'rel_ids', sql_type = 'int8[]' }, -- array with integers (for relation IDs)
+    { column = 'geom', type = 'linestring', not_null = true },
 })
 
 -- Tables don't have to have a geometry column
@@ -31,23 +31,12 @@ tables.routes = osm2pgsql.define_relation_table('routes', {
 -- it can be called any number of times and will lead to the same result.
 local w2r = {}
 
-local function clean_tags(tags)
-    tags.odbl = nil
-    tags.created_by = nil
-    tags.source = nil
-    tags['source:ref'] = nil
-
-    return next(tags) == nil
-end
-
 function osm2pgsql.process_way(object)
     -- We are only interested in highways
     if not object.tags.highway then
         return
     end
 
-    clean_tags(object.tags)
-
     -- Data we will store in the "highways" table always has the tags from
     -- the way
     local row = {
diff --git a/flex-config/simple.lua b/flex-config/simple.lua
index 513f4b92a..7a439ca0b 100644
--- a/flex-config/simple.lua
+++ b/flex-config/simple.lua
@@ -22,20 +22,23 @@ local tables = {}
 -- ids.
 tables.pois = osm2pgsql.define_node_table('pois', {
     { column = 'tags', type = 'jsonb' },
-    { column = 'geom', type = 'point', not_null = true }, -- will be something like `GEOMETRY(Point, 4326)` in SQL
+    -- In most cases we'll need a column for the geometry. The default
+    -- projection is Web Mercator (3857), so this will result in an SQL
+    -- type `geometry(Point, 3857)`.
+    { column = 'geom', type = 'point', not_null = true },
 })
 
 -- A special table for restaurants to demonstrate that we can have any tables
 -- with any columns we want.
 tables.restaurants = osm2pgsql.define_node_table('restaurants', {
-    { column = 'name',    type = 'text' },
+    { column = 'name', type = 'text' },
     { column = 'cuisine', type = 'text' },
     -- We declare all geometry columns as "NOT NULL". If osm2pgsql encounters
     -- an invalid geometry (for whatever reason) it will generate a null
     -- geometry which will not be written to the database if "not_null" is
     -- set. The result is that broken geometries will just be silently
     -- ignored.
-    { column = 'geom',    type = 'point', not_null = true },
+    { column = 'geom', type = 'point', not_null = true },
 })
 
 -- This is a "way table", it can only contain data derived from ways and will
@@ -65,29 +68,14 @@ for name, dtable in pairs(tables) do
     print("  name='" .. dtable:name() .. "'")
 end
 
--- Helper function to remove some of the tags we usually are not interested in.
--- Returns true if there are no tags left.
-local function clean_tags(tags)
-    tags.odbl = nil
-    tags.created_by = nil
-    tags.source = nil
-    tags['source:ref'] = nil
-
-    return next(tags) == nil
-end
-
 -- Called for every node in the input. The `object` argument contains all the
 -- attributes of the node like `id`, `version`, etc. as well as all tags as a
 -- Lua table (`object.tags`).
 function osm2pgsql.process_node(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     if object.tags.amenity == 'restaurant' then
         -- Add a row to the SQL table. The keys in the parameter table
         -- correspond to the table columns, if one is missing the column will
-        -- be NULL. Id and geometry columns will be filled automatically.
+        -- be NULL. The id column will be filled automatically.
         tables.restaurants:insert({
             name = object.tags.name,
             cuisine = object.tags.cuisine,
@@ -107,10 +95,6 @@ end
 -- information as with nodes and additionally a boolean `is_closed` flag and
 -- the list of node IDs referenced by the way (`object.nodes`).
 function osm2pgsql.process_way(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     -- Very simple check to decide whether a way is a polygon or not, in a
     -- real stylesheet we'd have to also look at the tags...
     if object.is_closed then
@@ -131,10 +115,6 @@ end
 -- same information as with nodes and additionally an array of members
 -- (`object.members`).
 function osm2pgsql.process_relation(object)
-    if clean_tags(object.tags) then
-        return
-    end
-
     -- Store multipolygons and boundaries as polygons
     if object.tags.type == 'multipolygon' or
        object.tags.type == 'boundary' then
diff --git a/flex-config/unitable.lua b/flex-config/unitable.lua
index 6c17ad8b3..8af35c75f 100644
--- a/flex-config/unitable.lua
+++ b/flex-config/unitable.lua
@@ -6,7 +6,6 @@
 -- OSM nodes are converted to Points, ways to LineStrings and relations
 -- to GeometryCollections. If an object would create an invalid geometry
 -- it is still added to the table with a NULL geometry.
--- XXX expire will currently not work on these tables.
 local dtable = osm2pgsql.define_table{
     name = "data",
     -- This will generate a column "osm_id INT8" for the id, and a column
diff --git a/flex-config/untagged.lua b/flex-config/untagged.lua
index b88955e39..e79a2f9f0 100644
--- a/flex-config/untagged.lua
+++ b/flex-config/untagged.lua
@@ -41,4 +41,3 @@ end
 osm2pgsql.process_way = do_way
 osm2pgsql.process_untagged_way = do_way
 
-