Hello, New here.
I have inherited a nightmare.
I have about 25 or 30 guns that were not cleaned properly or at all and paint has solidified in the guns.
I know that these are only $20 at Harbor Freight but Im hoping to recover at least some.
Is there anything I can do to recover these sprayers?
I have even tried soaking them in Muriatic Acid over night without success.

Thank you

Don't use any kind of acid - it will eat into soft metal components.

There are specialised chemicals which will dissolve paint but they're generally quite expensive and they're also potentially very dangerous. Full PPE gear is essential with these.

But, if these guns are just $20 specials I'd just chuck them in the bin. You'll probably use 20l of decent quality lacquer thinners to soak and then clean these guns. Not sure what your local prices are but a 20l drum of Multi-Mid costs me about $80 which is 3 or 4 of those rubbish guns or maybe half way to the cost of a good cheap one.

If you're going to soak guns, make sure you fully dismantle first. Especially remove any seals or plastic/rubber components, including air control valves. If the gun was decent I'd plan on replacing those with a service kit.

You'll also need a selection of small brushes including mini bottle brushes going down to about 0.8mm and up to about 12mm. Various other brushes and maybe some soft copper wires strands - again various diameters from about 0.1mm.

A few years ago I had a customer come in with a gun that hadn't been cleaned in ages. I told him that it wasn't worth it and that I would charge by the hour. Took me 2 hours to clean it properly (not including soaking time) and, at $80/hour I charged him $160. It was a cheapie and he could have bought 2 brand new ones for that, plus a 6 pack of stubbies.