I'm accumulating trash on my phone and I don't see a phone function to delete it. When I download a photo out of an email, look at it, then delete the email, the photo stays on the root directory but doesn't show up when I use the Gallery app. There does not seem to be any way to know it's there, much less how to delete it. If I download a PPT from an email, I can see it by opening QuickOffice, but there does not seem to be any way to delete files there either. If I download a PDF, I can see it with the Adobe PDF app, but again, I don't see a way to delete a file.
I can tether the phone to a computer and see all the files and delete them with no problem, but it just seems to me that there must be something I'm missing on the phone itself. Also, thumbnails. I can see huge numbers of thumbnails accumulating if I look at them with a computer, but unless I tether the phone and delete them with a computer, I don't see a way to even know they're there.