The easy straight forward answer is to wetsand it off using 150-220g.
without knowing what they used to coat it I can't rightfully suggest any one chemical/solvent. However,if you're down to try a couple I would suggest acetone first and if that doesn't do anything than you'll need something stronger. The problem is that some of the more aggressive strippers will also discolor the stainless underneath. If the acetone doesn't touch it then you can try dot3 brake fluid wich won't harm the SS.
after those it's onto oven cleaner or even aircraft stripper both of wich will discolor the SS.
if you do end up with some discoloration you can go back with light scotch brite to bring it back to a brushed finish.
Personally,I would start by trying to chip as much off as possible or wetsanding.