Tried stripping the black oxide off some new nuts and .75" screws for my BK16 mycarta scales. Left in vinegar overnight - nothing. Left in CLR for 3 hrs - nothing.
Left in Drano gel for 2 hrs - nothing. Went to bed. In the morning, they were still dark, but a little rusty. Brushed 'em off and agitated 'em in acetone. Let 'em sit.
Spent the weekend in Redding (CA) - usually one of the hottest spots around. Wasn't even hot enough to get in my sister's pool with my girls. MAYBE hit 80.
Came back after 5 days - fasteners still black, with a little rust, and a little scale. Cut to size and wire-brushed 'em on the Dremel - all shiny in seconds. (Now I know.)
Set in white vinegar 20 minutes, let dry 20 minutes, dabbed on a little mustard, let sit 20 minutes. Cleaned up with acetone. Nice patina to match the blade. Lubed, loctited, put it back together.
Very happy!
I'd take some pics, but they'd probably just look black. Either me or my camera sucks at details - and color rendition.