Spray gun cleaning, what solvents

[Terry, NJ]

I got lazy last year and hung up the spray gun, partially full of paint. Now what do I do? Plus, I have some HVLP guns that need a good cleaning. Again, I need the name of a good solvent to break it all down. I have lacquer thinner, but this is too aged for that. Most of the paints are PPG shopline (if it makes any difference) that I've used in it. I've heard of Acetone and MEK. Thanks!
Terry