[Dovecot] Delete antispam emails

I'm using dovecot with the antispam plugin to allow for training, but how do I delete emails once they've been trained? If I delete them from the folder using an email client they get retrained as valid emails when they're moved to the trash folder! D'oh.

I'm looking, ideally, for a solution that doesn't need a script to be run per user as I have a number of users using this feature. Also, the cleanspam script doesn't seem to be able to find the folder I'm using ('SpamTrain') so what format should I use?

Thanks.

david