I did have an oops with this. The madder was powered, but I had sense enough to not let it float free with the roving. Initially, it was contained in nylon stockings but at some point I accidentally poked one of the stockings when I was moving the dyeables around and ruptured it. The madder grit invaded the dye bath and is impossible to get out of the roving. The darkest sample in the image above actually felted during my attempts to remove the powder. The other roving piece I set aside an only lightly rinsed twice. It still has flecks, but will work to spin for a dye sample, even though I would not use the yarn for anything else for fear that the madder would release more dye and stain something else.
Up next... Experiment #2 - Weld Revisited! And following that I have birch leaves and bark to test.
As for what else is going on well... see below the 16 bundles of fine wool warp that is now on my loom!