I use this wonderful big tray. Years ago I was lucky enough to get 10 of this huge trays from a Dominos Pizza close by. At the time, I used them for marbling workshops - they're large and shallow and good for many things. Dominos used them as a dough tray - now they make perfect rusting trays.
I have been collecting rusty old things in a variety of shapes. I also look for "flat" things as they're easier to work with.
I soak the fabric in a white vinegar solution. I don't have an exact recipe but it's around 2 gallons of water to 2 cups of white vinegar. I soak everything for around 15 minutes - enough time for the solution to permeate the fabric.
I wring the fabric ever so slightly; it's really quite "drippy" when I put it in the tray. My fabrics are not lying real flat. I think the little pleats and wrinkles add some interest when you rust over them.
I then lay the rust objects over the top, no plan - just whatever happens, happens.
I sprinkle it with a little more vinegar/water solution and then loosely cover it with plastic.
I leave it around 24 hours. And then comes the most fun part - removing the rust to see the wonderful patterning. I've experimented with dyeing first and then rusting OR rusting and then overdyeing. I prefer to dye the scarf or fabric first to see what color I have to work with. This is a very pale piece which took the rusting very well.
All the scarves are dyed with an acid dye.
I like to work with 3 different silks - a crepe, a China and a chiffon; they all give different results.
I think the patterning is so interesting; you never know what you're going to get which makes it fun!