We have two Flow Mach 3 machines, we cut a lot of PVC and acrylic, the problem is we end up with nasty grey foam that floats on the top of the tank. We have abrasive recycling systems but obviously they aren't meant to handle floating solids.  Is there any good technique to removing the foam?  Currently we use just a pool skimmer type wand and obviously it takes forever and doesn't do a great job.