I just purchased a vintage accordion in great condition, and I noticed that they keys were nice and smooth compared to my other older accordions. I almost slip around on the smoothness of the keys. I am wondering if I should anticipate wear and tear on the keys over time. Do finger nails cut into the keys? I know on guitars and ukuleles that fingernail marks and strum marks are natural wear and tear on the instrument, but I did not know of any fingerwear on accordion keys. What are they even made of? I have Titano accordions, so I would think they would be constructed of decent material.