diff --git a/IV/Makefile b/IV/Makefile
index 709e1ba..ed53810 100644
--- a/IV/Makefile
+++ b/IV/Makefile
@@ -9,6 +9,10 @@ test: tests.sql .faux.db
 test-integration: .faux_filter-rivers
 	./db -f tests-integration.sql
 
+clean:
+	-./db stop
+	-rm .faux_filter-rivers .faux_import-osm .faux.db
+
 .faux_filter-rivers: .faux_import-osm
 	./db -v where="$(WHERE)" -f aggregate-rivers.sql
 	touch $@
diff --git a/IV/aggregate-rivers.sql b/IV/aggregate-rivers.sql
index 7d091f6..77ad483 100644
--- a/IV/aggregate-rivers.sql
+++ b/IV/aggregate-rivers.sql
@@ -24,7 +24,7 @@ begin
 end
 $$ language plpgsql;
 
-create temporary table aggregate_rivers_tmp (osm_id bigint, name text, way geometry) on commit drop;
+create temporary table aggregate_rivers_tmp (osm_id bigint, name text, way geometry);
 create index aggregate_rivers_tmp_id on aggregate_rivers_tmp(osm_id);
 create index aggregate_rivers_tmp_gix on aggregate_rivers_tmp using gist(way) include(name);
 
@@ -34,3 +34,4 @@ insert into aggregate_rivers_tmp
 
 drop table if exists agg_rivers;
 create table agg_rivers as (select * from aggregate_rivers());
+drop table aggregate_rivers_tmp;
diff --git a/IV/tests-integration.sql b/IV/tests-integration.sql
index ab6310f..3d93e8b 100644
--- a/IV/tests-integration.sql
+++ b/IV/tests-integration.sql
@@ -1,3 +1,5 @@
 \i wm.sql
 
-select ST_SimplifyWM_DEBUG(way) from agg_rivers;
+drop table if exists agg_rivers_wm;
+create table agg_rivers_wm (name text, way geometry);
+insert into agg_rivers_wm (name, way) select name, ST_SimplifyWM_DEBUG(way) from agg_rivers where name='Visinčia';
diff --git a/IV/wm.sql b/IV/wm.sql
index fddeb65..1541a13 100644
--- a/IV/wm.sql
+++ b/IV/wm.sql
@@ -328,23 +328,23 @@ begin
   mutated = true;
   foreach line in array lines loop
     while mutated loop
-      execute format('drop table if exists demo_%sfigures0', i);
-      execute format('create table demo_%sfigures0 (way geometry)', i);
+      execute format('drop table if exists demo_%safigures', i);
+      execute format('create table demo_%safigures (way geometry)', i);
       -- if anyone has suggestions how to insert a variable to a table without such
       -- hackery, I'll be glad to know
-      execute format('insert into demo_%sfigures0 select $1;', i) using (select unnest(array[line]));
+      execute format('insert into demo_%safigures select $1;', i) using (select unnest(array[line]));
       bends = detect_bends(line);
-      execute format('drop table if exists demo_%sbends1', i);
-      execute format('create table demo_%sbends1 (i bigint, way geometry)', i);
-      execute format('insert into demo_%sbends1 (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
+      execute format('drop table if exists demo_%sbbends', i);
+      execute format('create table demo_%sbbends (i bigint, way geometry)', i);
+      execute format('insert into demo_%sbbends (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
       bends = fix_gentle_inflections(bends);
-      execute format('drop table if exists demo_%sinflections2', i);
-      execute format('create table demo_%sinflections2 (i bigint, way geometry)', i);
-      execute format('insert into demo_%sinflections2 (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
+      execute format('drop table if exists demo_%scinflections', i);
+      execute format('create table demo_%scinflections (i bigint, way geometry)', i);
+      execute format('insert into demo_%scinflections (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
       select * from self_crossing(bends) into bends, mutated;
-      execute format('drop table if exists demo_%sselfcrossing3', i);
-      execute format('create table demo_%sselfcrossing3 (i bigint, way geometry)', i);
-      execute format('insert into demo_%sselfcrossing3 (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
+      execute format('drop table if exists demo_%sdselfcrossing', i);
+      execute format('create table demo_%sdselfcrossing (i bigint, way geometry)', i);
+      execute format('insert into demo_%sdselfcrossing (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
       line = st_linemerge(st_union(bends));
       i = i + 1;
     end loop;