I've had melted grocery bags, jacket liners, nylon back packs, boot soles and a plethora of similar glop over the years. I've never used oven cleaner, so I can't speak on that. I have used various 'softer than metal scrapers' (wood and plastic) - each has left scratches. My best luck has been to let it cook and polish with a mild to medium chrome polish at intervals as the crap cooks off. It takes time, but, leaves no evidence.
