I installed Firefox on a USB drive, and also in a TrueCrypt folder on my desktop. I searched for a bunch of images and then ran Recuva. Not one image showed. For anyone who missed my earlier posts regarding browsing tracks that are left behind while using Sandboxie and Returnil, I performed the same tests as above and Recuva recovered all or most of the images. So simply using a portable browser on a USB stick or in a TrueCrypt folder seems to do the trick. But I would assume that using Returnil and/or Sandboxie would provide the additional benefit of preventing the OS from creating copies and records of everything. I hope the new XB Browser works out because if it does, running it from a USB sticks should provide the best privacy ever.