Actually, you can buy a higher concentration of most chemical compounds at a hardware store. So ammonia with my quarter foul out, now cost is about $5, I just do a really complicated 15 minute cleaning by electrolysis. Wash out with water, heat barrel to get real dry, then patch out with oil.

A piece of insulated #14 wire 6' long, cut in half.
Two alligator clips
An all steel coat hangar
A 12" section of heat shrink wire coating
Two D cel batteries
A bottle of concentrated ammonia

Straighten out the clothes hanger, cut the twisted part off, sandpaper every bit of the varnish or paint off, put three or four small sections of heat shrink on the rod that you made from the clothes hanger. Put one section of the heat shrink on sticking out just past the bottom of the rod to keep it from grounding, one or two section in the middle and one section at the top of the barrel muzzle. This is to keep the rod from grounding out. Heat the shrink wrap to hold it in place. Strip both ends of the two sections of the #14 electric wire, solder an alligator clip on one end of each piece of wire. Plug the chamber, fill the bore with ammonia, insert the rod, clip the negative to the rod and positive to the gun metal. Put the two batteries together in series, stacked then wrapped with Duct tape, end of one wire connected to the negative and one to the positive. When connected correctly, the ammonia will start to foam.
The electrolysis transfers the fouling from the barrel bore to the rod. If it stops foaming, check the rod, if rod is coated, sand the exposed steel off and insert the cleaned rod again. At times, if the fouling is severe it can take a couple of cycles to get the barrel clean. However, the cleaning time is minutes not hours or days. Use this in my shop all the time. Cheap and easy to make and stores in a drawer.

Once made, the nickel foul out can be used over and over again, just sand the rod and you are off and running.