I have good news and bad news. The bad news is that the little cup of Valvoline PBR with the deposits in it was outside inside a zip-lock bag and the wind blew it off the table. The other bad news is that yesterday I added a drop of acetone and a drop of Amsoil Engine flush, without first taking a photo of the cup. That’s a problem because when I picked up the cup today, I saw the part of the hard, adhered carbon was significantly cleaned, and I don’t know how much I can attribute it to the Valvoline oil, the acetone, and the Amsoil Engine Flush. I was a sloppy tester this time. The good news is that something cleaned the carbon that I did not think would get cleaned at all. See photo below and compare it to the one in one of my above posts. The loose varnish deposit had swollen up considerably by the time I picked up the cup today. I’ve learned from past tests that that is what happens when varnish has been acted on by a solvent that is having an effect on it. It’s like how a dry sponge responds to water. Valvoline swelled it slightly and apparently the acetone and/or Amsoil Engine Flush swelled it up considerably more. It swelled to around twice its original size.