About stainless steel (ss) scrap
The three grades we see most are 304 (the standard food-grade stainless used in vessels, sinks and commercial kitchens), 316 (a marine and chemical grade with added molybdenum) and 202 (a cheaper manganese-bearing grade used in railings, furniture and decorative work). They look almost identical, which is why grade testing matters: sold blind, a 304 load can easily be paid at 202 rates.
Most stainless is only weakly magnetic or non-magnetic, but cold working can make even 304 pick up some magnetic response, so a magnet alone is not proof of grade. We use a spot test and, for larger lots, a handheld analyser reading that you can see.
Commercial kitchens, hotels, hospitals and dairies generate the cleanest stainless: tables, sinks, trolleys, vessels and hoods. Fabrication shops generate sheet offcuts and SS turnings, which are bought separately because swarf carries oil and needs different processing.