diff --git a/make/projects-dir.mk b/make/projects-dir.mk
index bb023694..c2b56e4c 100644
--- a/make/projects-dir.mk
+++ b/make/projects-dir.mk
@@ -129,7 +129,13 @@ pkg-install-prereq-release:
 	@$(PROJECTS_PY) requires-pkg --flavours "build run release" $(BUILD_PROJECTS) | xargs -r $(PKG_MANAGER_SH) install -y
 
 pkg-exclude-built-today:
-	$(JANWARE_PKG) built-today > $(EXCLUDES_FILE)
+	touch $(EXCLUDES_FILE)
+	$(JANWARE_PKG) built-today > built-today.tmp
+	cat $(EXCLUDES_FILE) built-today.tmp | sed 's/  */\n/g' | sort -u > $(EXCLUDES_FILE).tmp
+	mv $(EXCLUDES_FILE).tmp $(EXCLUDES_FILE)
+clean: clean.pkg-exclude-built-today
+clean.pkg-exclude-built-today:
+	rm -f $(EXCLUDES_FILE).tmp built-today.tmp
 
 pkg-list-groups:
 	@find . -name project.conf | xargs sed '/^ *group *=/!d; s/group *= *//; s/"//g' | sort -u