I once had an acrylic with four higher denomination chips from Harrahs Reno/Tahoe. First I broke them into four pieces so I could treat each chip separately. I tried freezing, heating, and hammer and chisel. Eventually I got them all out but they were all beat up and looked like crap. One at a time, I brought them to Harrahs and told them that my dog chewed it up. They cashed every one.