Never tried the underwear, mine usually end up like Stan's, pretty thin. I have found that my old socks work well though. I wear white, mid calf length athletic socks till they develop a hole, usually in the heel, then give them a final wash and retire them for cleaning. I can push the entire sock through a 12 bore with a stout cleaning rod (after a little scrubbing with Hoppes #9 of course) and they do a wonderful job of wiping things clean. My wife won't sew the socks and insists on buying me packs of new ones so I always have a nice supply of "cleaning socks" on hand.