Since it works so well on my hands, we'll see how it works on silk.
A silk scarf from the solar baggie dyeing unit in my Local Color class at Sievers could use more color. It hadn't been washed yet, so still contained tannin from the willow bark and bracken fern, as well as traces left by the vinegar assist and copper wire used to wrap the bundle. I put that and another piece of silk hot-bundled at Sievers in a plastic zip bag with a bit of cider vinegar.
It's hanging on the clothesline, where it will get full sun for a week or so. I did have to hit my hands with Reduran dye reducer after pitting cherries. Didn't want to risk transferring dye to my grandmother's embroidered pillow cases as I was hanging them out.
The rest of the pits are in the freezer to play with this winter, but I have another cherry pit experiment going in the rice cooker I found last week at the thrift shop. More on that next time.