Lindsey Bieda is a user on mastodon.social. You can follow them or interact with them if you have an account anywhere in the fediverse. If you don't, you can sign up here.
Lindsey Bieda @lindseyb

Does anyone know how I get blood plasma / tattoo gunk stains out of things?

@lindseyb i've heard everything from lemons to white vinegar to hydrogen peroxide. most places recommend soaking it in cold water overnight first. best of luck

@lindseyb at a completely speculative guess: follow a guide for removing blood stains, that should get most of it, and follow up with ink removal? that way you're getting the organics and the un-bonded ink up first, and you won't have to work quite as hard to get any remaining ink out.

@lindseyb Rinse under cold water, then hydrogen peroxide should do it. If delicate clothing, salt and water. Use toothpaste on dried.

@lindseyb Hydrogen peroxide (HOOH) works great on blood in fabric - must use an unopened bottle and watch it so you don't eat a hole in your fabric by leaving it too long.