From outside the coach where the slide enters the main body and just under the rod and gears is a small metal shelf behind the rubber flap (seal). Each time I extend the slide I feel the metal shelf for metal shavings, there's just enough room to get your fingers in there but be careful there are some sharp corners and edges there. Originally when I got the coach (July 2017) there were a lot of metal shavings. It was new so I chalked it up to that fact but since then I have checked it each time I moved it and found no more. True the rod is a square peg in a round hole and this will eventually cause issues, something to keep an eye on. I figure eventually I'll turn the square into a round end in the lathe and bore the bearing block and insert a bronze bushing.
USN - RETIRED NUKE