SWIC has just crumped them up with his hands, can be done in 50g batches at once and in bigger runs than a bean grinder. It takes about 3-4hrs to rip up 250g of al foil into 1" pieces, but only maybe 15 minutes to crunch them into little balls (roll the pieces between your hands, and you get nice tight balls formed). It works very effectively. Also, I gotta point out... always, always dissolve the mercury salt in the methanol before adding the foil. That was a silly point of failure a while back, resulted in not much fun being produced.