Copper pthalocyanidine (generally good-looking+most accessible that I know of, so I've stuck with that <3 :')), you can get it as powder online (cheapest+lightest) or as watercolor paint (it's called Pthalo Blue -- yes, of Bob Ross fame. Phalo Green has Cobalt IIRC, not the same, dunno about toxicity there. Check to make sure the dye is pure Copper Pthalocyanidine on the manufacturers website). I'm sure there are others, but the ones I've found don't bind nearly as well unfortunately, which is what we care about (transforming fabrics, proteins, compounds, etc to become an oligodynamic surface when not previously. As an aside, finding a silver compound of some sort that is A. Not damaging long-term, and B. acid-dyeing compatible would truly be my dream! <3 :')))))

Acid dye in a pot you don't care about as much (or not, it's your life!), citric acid in the canning section is the easiest to get. I use maybe 3-4 tablespoons or so. Add maybe a tablespoon of salt too.

Make it easier on yourself by putting warm water in the pot, adding the watercolor, and stirring until well mixed. Then run water from the faucet into the sink until it's as hot as it can get, and fill it almost all of the way. Then mix in your salt and acid. _Make sure you don't have bleach in your clothes, the acid will turn it into chlorine gas. In large quantities this can chemically destroy your lungs and if you're too far gone you'll suffocate. Not likely if you're careful, just adding the warning. If you've pre-bleached, rinse several times very thoroughly and soak until there is no more bleach remaining_.

Then add clothing, and heat water until it's maybe ~150-170 degrees or so, I just use a touch test (can handle up to 1-1.5 seconds) and err on the lower heat side, leaving it for a few hours. Stir and move the clothes so they have even contact with the water. Otherwise you'll get a blotchy dye. See Reddit for more details. I like the blotches, they're cute and add tons of personality.

Continue until the water is nearly clear. Acid dyeing will oftentimes soak up almost all of the dye in the water.

Let it cool, run it through several rinses in the washing machine. You can pour the warm liquid and clothes straight in. If you didn't have enough salt it might not be colorfast.

Repeat 2-3 times or more or until satisfied with the color.

You can also do this with your skin, a plastic barrier, and an (please be safe!!!!!!) appropriately warm heat source. For certain parts where skin cells rub off and give off an acrid odor when decaying, dyeing the outer layer lasts for about a week, looks a semi-deathly, semi-traditional-scottish-impression color of a deeper cyan blue, and resists bacterial growth for the time. As these cells are dyed, when they come off they will be self-sterilizing, reducing the off-byproducts afterwards. You can simply then rinse it off your clothing, and yourself, in a sink, shower, river, while traveling or the like, etc, etc. In the right circumstances, few people will be staring at your armpits, etc with the right clothing. :3 <3 :')))) <3

Also, if you have two gallon ziplock bags (nested, one as the 'outer catcher', be sure to remove air to keep all garments as submerged as possible, and you control your temperature well, and do not care as much about your water use, you can dye garments in a hotel room sink this way. You can also minimize water wastage (especially if the sink has an overflow system) by setting a continuous 'hot-as-possible' slow drip. Check it it 1, 2, and 5 minutes in to make sure the rate has not changed or the water temperature, when doing the drip method initially it can seem hot enough because the hot water is very "fresh", but slowing it down can cause an equilibrium where it is cooler due to the lag time in arriving from the water heater. (Also, if you do use this method in the future, please do let me know! I'd love to know someone else is doing this too and if there's any ambiguity, possible improvements, etc etc....)

As you can see, I am an absolute fanatic for low-resource, high-quality (or high-quality result, at least), engineering.

I could happily talk about this for hours or any particular usecase you might have, there are many ways to approach things. I've used these methods (among others similarly creative;P) to remove a surprising amount of weight from my backpacking kit, and I have much more flexibility too. This is also how I approach neural network research, but I love this domain as it's one that's directly relatable to many people, and somewhat allows me to be seen in what I feel I'm best at.

In any case, thank you for reading this if you made it this far, as I noted before, I would absolutely be overjoyed to talk about any usecases you might have <3 :)))) :')))) <3