I bought a 20 bore for a treat to myself this year. Anyway it was a bit short in the stock so before I had a proper butt pad fitted to extend the stock I bought a 15mm and 25mm slip on rubber pad to see which suited me best. Anyway. After a couple of months I have now removed it to find I has stained the stock. As you can imagine I am very angry about this but does anyone know how I can remedy it. There I quite a obvious mark on the stock which makes it look as if I've put a 3" stock extension on in dark wood. All help greatly appreciated.