evolution - removal of deleted items

[norman]

> > I was unable to empty the Deleted items file using Ubuntu 8.10 so I have
> > just upgraded to 9.04 and the problem is still there. I have just
> > checked and, to my horror, there are over 17.000 items there. Please
> > advise me on how to rectify this problem.
> > 
> 
> We'd probably need to know more information.
> Are you using POP or IMAP? Which provider?
> stuff like that...
> For instance, deleting stuff with POP from your ISP can be different 
> from deleting stuff with gmail and IMAP.

I did some research and found that I am not the only user to have
encountered this problem and it was suggested by removing this file the
problem could go away:- ~/.evolution/mail/local/folders.db. Being
ignorant in such matters I am reluctant to do this unless I can be sure
I would not lose those messages which are in folders I want to keep.
Have you any idea whether it would be safe to take this step, please?

Norman