diff --git a/dev/update.pl b/dev/update.pl
index 003984098e..31499d5367 100755
--- a/dev/update.pl
+++ b/dev/update.pl
@@ -42,8 +42,9 @@
 }
 
 if($new) {
-    # first remove oldies
-    system('find inbox -mtime +12 -exec rm {} \;');
+    # remove oldies
+    system('find inbox -mtime +20 -name "inbox*" -exec rm {} \;');
+    system('find inbox -mtime +20 -name "build*" -exec rm {} \;');
 
     # build md5 checksum file
     system("md5sum inbox/inbox*log > md5");