We have just bought a new dinner set and have found after a couple uses that the knife/spoon marks won’t come off .
We have tried Ajax, bleach , Bar Keepers Friend , Jiff . All recommended online , but no luck . Barkeepers Friend has given best results , but doesn’t remove completely .
317700cookie-checkKnife Marks On Stoneware Plates
It sounds as though the surface has been scratched. So it’s just a matter of using a product that is a strong enough abrasive, without damaging the surface. You’d probably get it off with fine grade wet and dry abrasive paper, but it would probably dull the surface.
One thing you wight try is automotive cutting compound (Kitten #3) from auto shops