Deleting junk mail with .zip attachments

I get at least 6 SPAM emails a day with .zip attachments that are supposed to be invoices or something. Norton utilities confirms these contain a package of malware. I have tried writing an Apple Mail rule to delete any incoming mail with an attachment that contains a .zip file but that rule has no effect. I have tried using the version of the rule if the file name CONTAINS .zip or has .zip at the END of the name. These are very dangerous files and it would be all to easy to double click on them to launch their attack. Any suggestions? BTW, it does no good to filter mail by subject line, sender, etc., because every one is different. I have at least 30 rules for those and a half dozen still get by every day. The one common feature they all have is a .zip file attachment ... something I never accept from an unknown email account.