diff --git a/src/wps/Makefile b/src/wps/Makefile
index 9c41962..adfd3df 100644
--- a/src/wps/Makefile
+++ b/src/wps/Makefile
@@ -2,7 +2,7 @@
 	@echo Nothing to be made.
 
 clean:
-	rm -f *~ *.o *.d
+	rm -f *~ *.o *.d *.gcno *.gcda *.gcov
 
 install:
 	@echo Nothing to be made.