the daily grind

This week I noticed my salt mill had stopped working.  On inspection of the grinder mechanism, I found the reason that it no longer ground the salt was because the grinding area had worn smooth.  There was also evidence of small plastic flakes coming off the mechanism (follow the arrow in the image).  I had no idea salt could be so abrasive and also wonder how much plastic I've been grinding/counsuming in my food?  As it happens I'm working on another pepper mill at the moment, more on that to follow...