diff --git a/Makefile b/Makefile
index d03de53..9978ca6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,9 @@
 all: rebuild-switch
 	date
 
+clean:
+	nix-collect-garbage -d --delete-older-than 15d
+
 rebuild-switch:
 	nixos-rebuild switch