Exim and frozen error mails

[Christopher Wolf]

My exim tends to gather frozen messages caused when a fake email address 
tries to deliver to a no-longer existing email address on my domain.  It 
generates an error response saying that user does not exist, but it cannot 
deliver the error to the fake user nor the intended address on my server, 
so it just freezes the message.

Is there any way to get it to just throw these away, even if it's just 
after some amount of time?