re: Change of mind

What kind of marks? Maybe it’s just dirt?

Some water based finishes turn milky color if you put something hot on it like a coffee cup. I don’t think mineral oil does that.

I still think your best bet is a good mineral spirit wash, light sand to knock any raised grain down, then oil varnish, which still mix in with the other oil (you’re not getting rid of all of the mineral oil without planing the surface quite a bit, I think) and the varnish will give it a seal coat. Then if you want even more protection, a light coat of wipe on poly. That should stand up pretty good to regular kitchen use. You have to tell them that it’s not stone, and even natural stone can stain if abused. Some common sense goes a long way.