I've been using paint thinner to clean my spray gun. Is there anything better to use?

Paint thinner is the "norm" amongst most, including shops however, shops use gun washing machines set on timers [kinda like a dishwasher].

IF, you have a gun thats been neglected, say has an extreme build up of paints, lacquer thinner is slow to work.
In extreme cases, I dismantle the gun [be sure to remove fluid tip packing & air valve] & place parts [except cup] in cake/casarole pan.
Poor over the top air craft stripper until parts are submerged.
I ususally leave this soak anywhere from an hour to overnight, depending on build up.
The cup can be cleaned on your work bench by brushing aircraft stripper on w/a paint brush [let it soak in stripper, dont let stripper dry out].
When ready, wipe majority of stripper away w/rag, then follow up w/thinner bath.
Ive been doing this for past few decades, w/great results.BE SURE TO RUN MUCH THINNER THROUGH GUN!

I use MEK (methyl ethyl ketone), available for about $12.00 a gallon from OSH, ACE, home depot, etc,... ACETONE also works, but evaporates so quickly, you really cant use it.

MEK is in alot of paint bases, dissolves just about everything from laquers, to urethanes and will make short work of even neglected polyester primers, left to dry in a gun.

Soaking the parts in it will work if it's really fouled up.

NOTE!! this stuff will eat right through a any painted surface in seconds, so make SURE you dont get any on any painted parts, and wear the respirator while using it, it's quite noxious.
HIGHLY FLAMMABLE use the obvious precautions.

your going to want to use mek in a highly ventilated...outdoors area. the fumes are extremely strong and make for a nice headache if you breathe them in too much. we use it a lot where i work to clean metal parts in the machine shop.

There is a product called Gun Cleaner sold by the gallon, most body shop supplies have it. What I use is a homemade contraption that works wonders on very old or dried paint. I mix half a cup of Aircraft stripper to one quart all purpose laquer thinner. This mix really makes your gun clean, just soak the parts of your gun in the mix and it cleans it in half the time.

I've never heard of aircraft stripper. Where is it available, and does it go by any other name or will any paint store, or auto body store know what I'm talking about.