I was just going to post this. I read a lot and my Paperwhite fills up with those deleted books and empty SDR folders. In my old Keyboard Kindle there was something I used that I could clear out all the empty folders but that didn't work on the Paperwhite. Until now.
My Paperwhite just starter stuttering a little and I realized it probably needed cleaning so I started looking and
found this:
One Click Clean Useless sdr Folders in Kindle
http://www.ereader-palace.com/one-cl...olders-kindle/
It's in Chinese but the page translates it for you. It works great! It says "not responding" while it's working but that's just because it's searching. Mine found 488 SDR empty folders!