I use corncob with A LITTLE polish added (happens to be Midway's). Too much polish and the mix clumps up in the case. Then maybe 20 minutes in untreated corncob which removes all traces of polish. I have a small compressor in the garage so it's quick and painless to blast any pieces of corncob from the flash hole. Kinda fun really.
Obviously I resize first so resizing lube gets polished away. Cases never have gotten so gritty that I had to worry about damaging a die, at least after a quick roll in an old towel.
