I used a steel wool pad for these rust dyeing experiments. I unrolled the pad, put it on top of two pieces of white fabric, wetted it with lots of water and a little vinegar. I rolled everything back and put it in a plastic bag. After one day, it was already very rusty. This is the fabric that was close to the pad.
This is the second piece of fabric, the one that wasn't touching the pad.
After the first experiment, I did it again, but I used just one layer of fabric. I forgot about it for two days. Today I opened the bag... The pad has fallen apart, and the result is completely different from the first time.
Here's a detail. I like the texture very much.
Another piece of fabric is still rusting, folded around an old tool. But the process seems to be much slower. I'm going to leave it for one or two more days.