Scotch brite has aluminum oxide in it. It can embed in bearing and trash an engine. If the parts were washed after being cleaned, you should be OK. GM has a bulletin about roloc© discs (essentially the same as scotch brite) being used during intake manifold replacements, and the potential damage that can result from their use. I have seen an engine that was destroyed by their use, so it isn't a mechanic myth. I now avoid their use unless the parts can be washed in a parts washer. Scrapers, brushes, and razor blades only on engine blocks or parts that stay on the vehicle. There are the bristle discs, but they have a ceramic abrasive in them and aren't approved by some manufacturers on engines either. Very small surface imperfections are OK, that's what a gasket is for. If a razor blade gasket scraper won't catch on it, I call it good and clean with brake clean.
