I would soak it in water and then gently scrape it off.

I use EasyOff Fume Free (in the blue can; not yellow) to clean those buildups around my grill and oven. Just spray on and let the foam sit for about an hour and wipe with a scrubbing pad or fiber scrubber.

Actually, the oxide layer from overheating on stainless steel is colorless. As you know, you can see a rainbow color reflection of oil slick on water when in fact oil is basically colorless. Or rainbow color on soap bubbles. The reason for the color is that as light (white light ) hits the ultra thin layer of oil, the reflection cancels and reinforces each wavelength because the thinness of the oil is very close to the wavelength of light. Same with the oxide layer on S.S. it's very thin, the color of discoloration depends on how thick this layer is from overheating. Yes, BKF works because it is an abrasive and an acid, it can remove and dissolve this oxide layer. dcarch.

Christyne Ponchron: "I read on BFK’s website that it is not safe for stainless steel. Could take the finish off?" This may be referring to the "fake" finishes such as black stainless steel which has a polymer (plastic) coating that can be easily scratched and damaged. Stainless steel itself is an alloy of steel and chromium, with carbon, silicon, and manganese, and sometimes other metals such as nickel also added. The chromium component causes a very thin layer of oxidation on the surface, effectively preventing further corrosion or rusting. The oxalic acid in BKF removes the oxidation layer, which quickly reforms itself to a fresh surface. That's the point of it. BKF is mildly abrasive so a highly-polished stainless steel could be scuffed by aggressive rubbing. Rubbing with the polish marks (grain) helps avoid the risk. I used oily polishes for some years but they caused various degrees of smudging and smears. Initial use of BKF removed all that oily mess to a fresh gleaming finish, with reuse of it only as needed (not much) to remove water drips, fingerprints, and mineral residue (kitchen sink, hard water).