26-08-2020 With subtractive machining processes, the discussion eventually turns towards what to do with the collected leftover bits. While CNC mills have to worry about material chips and oils, abrasive waterjet users have to deal with spent abrasive. With abrasive feed rates capable of exceeding 2lbs a minute, that spent abrasive can accumulate at a very rapid rate. What to do with that used abrasive tends to fall into three categories: disposing, recycling, and repurposing.