I've just started work on a couple of BSA Meteor MkIV and a few Scorpion pistols. They have obviously not been used for years and the pistons/buffer washers are stuck solid.
I've always struggled with this type of job and have a sample of each stood up in a corner. One has the barrel and air chamber full of Isoprop. and the other Acetone. They have been like that for 2 days and still nothing is moving.

Is there any chemical I can obtain that will free off or dissolve the awful stuff that BSA make the bits out of.
I have removed similar stuck pistons on other guns by making wedge bolts but I son't want to do that with the BSAs because of their flimsy folded construction

Advice please?