I'd like to soak the entire barrel and receiver at once. Using mineral spirits as soaking material,
I have made a soaking tube or container, for my side-lock M/L's. The last one I made, was out of 2" PVC, cut to length. I glue a flat plug on one end and have a removable cap for the other. I plumb clamp this tube, in a verticle position, insert my barrel, breech down, fill the tube with mineral spirits to cover the muzzle end. Install cap and let it soak ....
Our M/L classes, last all day and normally shoot about 75 rounds. We usually use one sidelocks and keep an in-line, in reserve. When done, I give all a cursory was or wipe, with Ballistol. By the time I get back to my shop, I'm fairly tired and lazy. I just diassemble, drop the barrel in the tube, walk away and let it soak for about three days. As long a I keep my barrel, submerged, nothing will start to rust of corrode. .....
Be Safe !!!