Dyeing fabric with rusty metal

A new one on me, which surprises me, you'd think I'd have heard about and tried this years ago, one of my business names is Rust and Lace.
I have ruined fabrics with rust, never thought of making them pretty with it!
Quilting Daily "From Old Metal to New Textile: Rust Fabric Dyeing"
They basically pile things that will rust (or my my eyes, are already rusty) where they want them on cotton fabric (that's ready to dye) and spray vinegar to make it transfer rust and make a washable fabric.

Neutralize the fabric by placing it into 4 gallons of water mixed with 1/4 cup salt. After neutralizing, the fabric can then be washed in soap and water.

Well now... I have a garage full of tools I've been de-rusting.... I think there may be some function stacking happening here soon!

How creative! I'm a tree-hugging tye-dyeing enthusiast. Here's a couple more resources.

Other natural dyeing sources

Food scraps you can use for dyeing

Plants you can create dyes from

Thanks for sharing!

p.s. I just saw this, too! https://permies.com/wiki/157744/dyeing-natural-materials-notes-natural#1236231

Okay, that's neat! If you want it two-coloured, you could paint some parts with a strong tannin solution, like bark decoction or such. Tannin plus iron makes ink, so probably a blueish black colour (haven't tried ink-making myself yet, been meaning to). And if you want to un-dye some patches, oxalic acid forms a transparent complex with iron ions (not sure if with Fe2+, Fe3+ or both.) This is useful for removing iron stains from bark-tanned leather as well...

I tried rust dying about 10 years ago, when I first heard of it.  It can be lots of fun, and I love the suggestion of adding tannins to the mix.

I dyed both cotton and silk.  Both took the color without mordant… though iron is used as a mordant, so perhaps my statement is not accurate.  I should say without additional mordant, which leads me to possibilities I did not investigate, such as adding various mordants to the process, alum, chrome, tin etc.  If tannins get you into the bluish realm, what else might be awaiting us?

One thing I discovered that might be good to know, it changes the hand of the dyed fabric.  The light weight silk was stiffened, and so was everything else, but being so light and soft, it was most noticeable on the silk.

Of course I made up a story for myself, about what could explain the phenomenon!  I think the iron itself, a large and heavy atom? ion? molecule? attaches itself to the fiber, the amount depending on how dark you dye it.  And how can that not make the formerly light and “fluffy” fibers of the textile stiffer, heavier, scratchier?

All the same, it’s a wonderful process to experiment with!