I've got maybe 1% of the plastic left after many brushings and soakings. I couldn't find a tornado brush but I did find some #3 steel wool, which I wrapped around a 16 gauge brush that had first been wrapped with a paper towel (to keep the wool out of the bristles. I should have it all out shortly.
I've used windex for bp fouling in rifles, but I've never battled plastic like this.
I'm probably being stupid but I am going to try this again with the plastic shotcups but this time, I'm soaking the fiber wads in bullet lube. I think it will give a much better seal and save the cups from melting. It's the working hypothesis anyway. Next Wednesday, we will know.
Brent