diff --git a/IV/Makefile b/IV/Makefile
index ed53810..f55b893 100644
--- a/IV/Makefile
+++ b/IV/Makefile
@@ -9,10 +9,17 @@ test: tests.sql .faux.db
 test-integration: .faux_filter-rivers
 	./db -f tests-integration.sql
 
+.PHONY: clean
 clean:
 	-./db stop
 	-rm .faux_filter-rivers .faux_import-osm .faux.db
 
+.PHONY: clean-tables
+clean-tables:
+	for t in $$(./db -c '\dt' | awk '/demo_|integ_/{print $$3}'); do \
+		./db -c "drop table $$t"; \
+	done
+
 .faux_filter-rivers: .faux_import-osm
 	./db -v where="$(WHERE)" -f aggregate-rivers.sql
 	touch $@
diff --git a/IV/wm.sql b/IV/wm.sql
index a2b804d..4954f13 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_%safigures', i);
-      execute format('create table demo_%safigures (way geometry)', i);
+      execute format('drop table if exists integ_%safigures', i);
+      execute format('create table integ_%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_%safigures select $1;', i) using (select unnest(array[line]));
+      execute format('insert into integ_%safigures select $1;', i) using (select unnest(array[line]));
       bends = detect_bends(line);
-      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;
+      execute format('drop table if exists integ_%sbbends', i);
+      execute format('create table integ_%sbbends (i bigint, way geometry)', i);
+      execute format('insert into integ_%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_%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;
+      execute format('drop table if exists integ_%scinflections', i);
+      execute format('create table integ_%scinflections (i bigint, way geometry)', i);
+      execute format('insert into integ_%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_%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;
+      execute format('drop table if exists integ_%sdselfcrossing', i);
+      execute format('create table integ_%sdselfcrossing (i bigint, way geometry)', i);
+      execute format('insert into integ_%sdselfcrossing (i, way) select generate_subscripts($1, 1), unnest($1)', i) using bends;
       line = st_linemerge(st_union(bends));
       i = i + 1;
     end loop;