diff --git a/test/threads/Makefile b/test/threads/Makefile
index 58cdf18..59eb4f2 100644
--- a/test/threads/Makefile
+++ b/test/threads/Makefile
@@ -46,4 +46,4 @@
 	g++ -o ThreadsClient $(CFL) ThreadsClient.cpp ./gen-cpp/ThreadsTest.cpp ./gen-cpp/ThreadsTest_types.cpp
 
 clean:
-	rm -fr *.o ThreadsServer ThreadsClient gen-cpp gen-py
+	$(RM) -r *.o ThreadsServer ThreadsClient gen-cpp gen-py