I just used some sandpaper and flushed with the garden hose. There was a few straglers that used a thin file on. Also let it sit or run in near boiling water for an hour to get the initial chemical leaching out.
I would try using sand paper in the slots followed by a good wash and rinse. You could use a dowel to ream the interior ramrod style. That should remove the majority of the cuttings.
I ran a half inch drill bit down through the sections in mine, this cleaned up most of it, then just a quick utility knife blade through the slots to break off anything that might be left hanging, works very well and was fast.
I know that it's a bit late, but one solution is to put a 1/2" wood dowel rod inside the CPVC pipe before cutting the slots. When you remove the dowel most of the burrs will come off with it.