Mailbox attachments - storage card - do I need all of these?

[RED_RAIN]

I flash new ROM versions a lot.

I have probably 20 "Inbox.mst30032059.163457536" or some other numbers in my storage card now. I only have 3 email accounts at any given time so I'm guessing some of these aren't needed.

How do I tell which ones are currently being used and can I safely delete the others?

Heck, if I can't determine the above, what happens if I just delete all of them, when I go back and download an attachment will it automatically create new folders?

Thanks