I've tried that rubbing alcohol and salt mix, it worked wonders. However, if you want to try to save some of your res for a rainy day, you could always hold a lighter up to the chunks you're going to scrape off so they're nice and easy to move around. Then just get a saftey pin or something of that sort.

My goal is to get a ball of res bigger than my head. Then I would make it into a face and call him Pugswell Twinklebottom. Oh, my friends would say "Stop wasting hits on that damn ball!" But Pugswell and me would just laugh.