If the oil used to finish the countertop does not contain wax, then epoxy finish can be applied without any issues. However, if an oil such as Polyx by Osmo or Oil 2C by Rubio Monocoat has been used, the answer is no.

If the oil finish does not contain wax, clean the surface with a soap such as Black Soap or a soap designed for natural oils. Once the surface is completely dry, apply a thin coat of coating epoxy and let it dry for 24 hours before applying the final coat.