IMHO - anyone working on these old cars - should have a supply of Kroil Penetrating Oil in their garage. While ATF/Acetone may indeed work a bit better - I don't like the thought of using Acetone on anything. Kano Lab's Kroil is without question the best available Penetrating Oil that you can buy. That and it actually smells pleasant, while it won't destroy any painted surfaces. Yes, it is a bit expensive when you have to pay shipping costs - Nonetheless if you use it, you'll not likely ever go back to anything else. It works wonders - far better than the stuff you buy at the AutoParts Stores. Kroil - Aero-Kroil is the aerosol can. Try it "Risk Free" - with their current Buy One of anything - Get One Free. Two Can's will last the average person a year to two. https://www.kanolabs.com/orders/order_kroil.shtml FWIW, Carl B.