We've got a couple of non-stick fry pans whose outer surfaces just won't respond to any of the cleaners we've tried. These are fairly heavy, so we're pretty sure they're "stainless" (?) steel.
They most likely were purchased at a Linens & Things (several years ago) and are both made in China. The outer bottoms have a repeated wave pattern in them. The stains are orange-ish rusty looking and now pretty much cover the majority of the outer bottoms and sides.
We've tried Barkeeper's friend (usually works on everything), Comet, 3M stainless cleaner, and several kinds of metal/brass/copper cleaners.
I've seen some online suggestions for baking on mixtures of cream of tartar and a couple of others I can't recall. Anyone have something that should work??