[Exim] rejecting HTML-ized mail with central_filter

Is there a way to have a central_filter reject HTML-ized mail for a user?
Even a forward file to delete it would suffice.

I am having problems with my central filters when I attempt to save some
mail to a file.

I had this problem with my system filter and solved it with:
message_filter = /var/mail/block/system-filter
message_filter_directory_transport = address_directory
message_filter_file_transport = address_file
message_filter_pipe_transport = address_pipe
message_filter_reply_transport = address_reply

Can I do this for a central filter also?


thanks

--
Andrew