diff --git a/lib/Makefile b/lib/Makefile
index a48239850..6aad7c83d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -1,3 +1,7 @@
 all:
 	python setup.py build_ext --inplace
 	rm -rf build
+clean:
+	rm -rf nms/*.so nms/*.c
+	rm -rf utils/*.so utils/*.c
+