I learned this the hard way while I was at the Dustin workshop.
I noticed that my translucent clay kept getting stuck in my PM and I needed to run it thru on the thinnest setting for the technique that we were learning! What a mess.
I didn't even imagine that was PM was soooo full of clay bits! After all this was my spare machine, the one that I ONLY used when I travelled to classes and the SOPCG meetings! Who would have thought.
I DIDN'T