diff --git a/Makefile b/Makefile
index 2e3ba0d..5db0a30 100644
--- a/Makefile
+++ b/Makefile
@@ -43,3 +43,4 @@ rsc: $(GEN_RSC)
 
 clean:
 	rm -f $(HTML) checksums.json
+	make -C contrib/ clean