I know... I know! I'm on a tangent with the rust-dyeing, but I loooooooooove the color of rust! And I needed to figure out why I wasn't getting good impressions with some methods, but was getting them with others. I finally figured out that the cloth and metal items didn't need to swim in a vinegar bath! Yesterday I soaked a cloth in vinegar, wrapped several bolts with metal wire, and left it in a margerine tub, occasionally spritzing with water. Today it spent the day on the deck, and when I unwrapped and washed, I got the results I had hoped for! Here it is:
The bolts and wire I used had been gathering rust for a couple of weeks now, what with my failed attempts and all. So the secret here is 'less is better' on the vinegar front!