Matt, for some time now the four remaining casinos that have strike machines have been using clad $10 strikes. Except for the red caps which are still .999 fine silver. And yes at the 4 QQQQ's along with Sam's Town you can trade 20 clad $10 strikes for one $200 .999 silver strike. You should call the cages before going to make sure they have any of the $200's though as generally they trade out quickly.

hope this helps,
Dennis