From time to time I see scrap marks on rocks on a trail. In the past someone wrote they were from crampons. But I don't think so. I think they maybe be from the ski/hiking poles. They didn't seem to be an issue. However When I did the Baldface loop they seemed to be everywhere and it was very hard not to notice them. They even marked up flat sections of rock. Sometimes over 20 of these white scraps on a rock in one place. Does anyone know for sure what they are from. Sorry I don't have any pictures of it. I use a hiking stick or sticks if my knee is hurting so I could not test it out with a hiking ski pole. If they are from these poles I bet a different tip would prevent it from happening. Maybe a wooden tip that wouldn't fall apart easily or pollute like a rubber or a plastic one. I would use the poles but I hate the noise they make so I stay with the stick (for now) but I know how important they are to protecting and helping the knees.