I don’t know about the cases (other than they are Velo-Dog) but want to comment on Muriatic acid. It sounded like you have not used it before. If this is not news to you, just ignore what I’m saying. But maybe others who have not used it can learn something.
Yes, it is the same as Hydrochloric. I think the name “Muriatic” sounds less threatening than Hydrochloric. Anyway, I buy mine at Ace Hardware in gallon jugs. I think it’s about 35% solution. Comes in handy for cleaning lots of things around the estate. We had a big forest fire several years ago and my house was “slurried”. The only thing that removed some of the red dye was diluted muriatic.
You do need to be careful using it. The fumes can knock you on your butt and it will instantly disolve certain things, like concrete, shoes, skin, and your Sunday suit, so test a small area before proceeding. It’s always best to dilute it with water (pour the acid into the water) and then increase the strength as necessary or desired.
As far as cleaning cartridges - it will sometimes tend to seperate the two primary metals, zinc and copper, leaving blotches of copper that cannot be removed. So be careful there.
Other collectors will object to using Muriatic but there are times when it’s the only thing between a junk cartridge and one that is a little more decent looking.
JMHO as usual