Actually that’s kinda not true. Adamantium is indestructible pretty much. It can’t be blemished , can’t oxidize , it’s always the same . Just like diamonds or think in terms of the Scientific hardness scale. It rates hardest known substances 1-10 ( 10 being the hardest and diamond) only a substance above another on this scale can scratch or alter one below it . Diamond trumps all.
Adamantium would not be affected being inside Wolverines body at all. I prefer lightly polished satin type finish for me