Cat licks fireplace

Three year old female tortie cat in perfect health….

My fireplace is slate, and once every couple of years I have to wipe it down with baby oil so that it doesn’t discolor. Like it fades out and I have to oil it so it will stay black. For whatever reason, this year my cat is fascinated with the fireplace and keeps licking it. I’ve covered it with blankets so she can’t get to it but I’m wondering if I should scrub off the oil. It’s been two weeks and this morning she was trying to pull the blanket off to lick it again. I can’t imagine that there is any oil that’s not been absorbed but I’m still concerned she will poison herself.

I guess my question is: should I scrub it off, could it really hurt her? It’s been absorbed but I could scrub off the top layer.