If you've been in a faction and were added to the corresponding forum and have since been killed/left and it makes no sense for you to still have access, you can remove yourself without a DM's aid:

Click on 'Usergroups' on the panel beneath the logo on the forums. Then choose the relevant group, press 'View Information' then there'll be an 'Unsubscribe' option.

I've got alot of requests for this sort of thing, so I thought I'd let you all know! Also, please make sure it's something you remember to do.

Thanks!