Tried Purple Power Tonight
Actually, it was a competitive brand ('Super Clean') sold by Menard's. Had 8 chains ready to sharpen - half good chains, and half salvaged chains. Thought I would try it.
Very impressive. Used a 50/50 mix with water in a plastic tub, a few swishes, a few rinses in another tub, and voila! Literally, just a few seconds. I thought I would have to soak them, or brush them, or shake them in an old peanut butter jar. A few of the older chains took a few light passes with an old toothbrush to get rid of some crud under the cutters, followed by another rinse.
I am still a little concerned about washing out all of the lubrication around the rivets. Hung them to dry in a warm place, and hit them with WD-40 to penetrate and displace any remaining moisture.
Philbert