I'm too lazy to read all the posts, but has anyone mentioned dyeing with used coffee grounds? It's slightly messier than tea or brewed coffee, but it makes use of what would otherwise be waste and I think it might have a little more lasting dye effect (personal experience opinion).
Just dump the used coffee grounds from a basket-type drip machine(what everybody in North America will call a "coffee maker"... might be different in other countries who use screw presses or lab glass percolators) onto your fabric and fold it loosely into a flat little bundle.
Put this at the bottom of a dish or bowl and add some boiling water -- just enough to soak the bundle, you don't have to submerge it. Squish the bundle up and down a few times (like using a plunger) with a potato masher or the back of a spoon or whatever works, just to soak the fabric. Now let it sit until the water cools off.
To strengthen the dye effect, put the bowl with the bundle in the microwave and re-heat it. If it dries up after multiple reheatings, add some fresh boiling water. :loveliness: