diff --git a/make/projects-dir.mk b/make/projects-dir.mk
index 0a5a29ac..e77843fe 100644
--- a/make/projects-dir.mk
+++ b/make/projects-dir.mk
@@ -262,7 +262,7 @@ pkg-%: $(filter-out $(UNAVAILABLE_TARGETS),pull.done)
 # --- generic cleanup targets
 
 clean-dirs:
-	echo $(sort $(dir $(wildcard */*.done))) | xargs -r $(PROJECTS_PY_BUILD) clean
+	echo $(sort $(subst /,,$(dir $(wildcard */*.done)))) | xargs -r $(PROJECTS_PY_BUILD) clean
 
 clean-all-dirs:
 	$(PROJECTS_PY_BUILD) clean $(PROJECTS)