I have the toenails of a crusty old pirate. Just covered in barnacles. Today after grinding them down with a hacksaw, I decided they needed some freshening up. Girlfriend had mentioned that Vick’s Vapor Rub can help. True you need to do it consistently for 300 days straight, but I figured anything was better than nothing. I smeared some rub on the barnacles then put on my socks.
I was assaulted almost instantly by Biscuit. He nuzzled his way into my foot purring loudly. I may as well have danced in catnip. He started licking my toes happily. It was a weird but not unpleasant sensation. I probably would have let him lick the barnacles clean off, but I suspected vapor rub was not kitty friendly. I banished him from the room and aired out my soggy sock.
Let me know if you have any toenail care tips that are cat compliant.

The vinegar/listerine mix is supposed to work too. Also takes a long time though.
I don’t remember if Biscuit is into it or not.