How to delete/purge tickets?

Well, I’ve a lot of trash in my RT queues and I don’t know how delete them.
I’ve another problem, my database is really big Attachments table, for example, acctualy uses 600Mb, how can I clean this table??

Rodolfo Sikora - Dpto. Técnico - Analista
INOVA Tecnologias Ltda, Brasil
http://www.inova.com.br