stainless steel processing: cut with arc welderand still be considered clean?

I would cut a couple of pieces and take it in to see what they call it. It may be fine with the splatter. If not, you might be able to cut it then hit it with a heavy scraper. If that won't work, try running a grinder over the splatter. It will probably come off pretty quickly.

Depending on the amount you have, it can actually be worth quite a bit more cut to size. I had two semi loads of 20 foot conveyors that I had to cut down to 4x4x4 foot sections. It was a 20% difference in the price at the time. I did use my plasma cutter on it, but you have to have a lot of SS to justify buying one.