Nothing you couldn’t recover from unless he managed to crack it. I’d wipe it down, and hit it with brake parts cleaner. If I was still nervous about contamination, I’d put it in an oven with the self cleaning function and run it. That should burn it back down to bare metal. A good scrub with dish soap to remove any residue and a good seasoning. I don’t know if I’d personally skip the heat clean step or not, but I’d definitely put it back in usage.