diff --git a/make/lo.mk b/make/lo.mk
index c4943c61..6327241a 100644
--- a/make/lo.mk
+++ b/make/lo.mk
@@ -29,7 +29,7 @@ install: $(INSTALLED_LOADABLE_OBJ_LIBS)
 clean: clean.lo
 
 clean.lo: profclean
-	rm -f *.o *.cpp *.so *.done *.dll
+	rm -f $(filter-out $(CPP_PREFIX)%.cpp,$(wildcard *.o *.cpp *.so *.done *.dll))
 
 $(SO_PREFIX)%.so $(SO_PREFIX)%.dll: %.o
 	$(CPP) -shared $^ $(LDFLAGS) -o $@