+1 for this, but why not just one option to "Clear Internal Cache Folders" and get 'em all. This could be made "..On Exit," or as a button to do so when clicked.
It could be implemented in many ways. I just didn't notice any of the other cache items taking much space, but a clear cache after xx days would be one way to implement that function, depending on the specific function of the cache. But, I think I agree to an option to just clear it all on close.
Well, this is why I stated it as I did original. I don't know exactly. When I use MB to tag my music, I tell MB it to embed the image of the album into the file, so it never has to redownload it, and then the file itself is portable no matter what.
I still think the clear on exit would be nice. I don't mind having to download images during the day. They're small and I have plenty of bandwidth I pay for.