[exim] acl to drop messages addressed to specific recipients

Hi there,

is there anybody out there who successfully implemented an acl_check_rcpt to
drop messages to specific recipients?

A lot of once valid and now non-existent accounts on the machine are only
used to be spammed.
Collecting all the typo mails in postmasters account I get mad by scrolling
through all this useless stuff.

Thanks
Frans