If you're trying to discard/delete the attachments outright, you could
use the following conversion channel entries,
out-channel=*; in-type=*;
in-type=application; in-subtype=*;
in-parameter-name-0=NAME; in-parameter-value-0=*.bat;
out-type=text; out-subtype=plain; out-mode=text; out-encoding=none;
delete=1
out-channel=*; in-type=*;
in-type=application; in-subtype=*;
in-parameter-name-0=NAME; in-parameter-value-0=*.exe;
out-type=text; out-subtype=plain; out-mode=text; out-encoding=none;
delete=1
out-channel=*; in-type=*;
in-type=application; in-subtype=*;
in-parameter-name-0=NAME; in-parameter-value-0=*.scr;
out-type=text; out-subtype=plain; out-mode=text; out-encoding=none;
delete=1
In this case, the message will still be passed thru, but the
attachment will be deleted. This is actually a pretty nice safety
net given the number of viruses coming in these days.
Hope this helps.