get some gravel and a old clothes dryer and put the gun, gravel and turn on the dryer for about 4 hours and all the paint will be removed.
now, if you do that, then you are responsible for how it turns out. but you can use anything. straight water with a microfiber cloth. 50/50 of h2o and isopropyl, or some windex. if its a Mag, then dunk it in a bucket full of water. if its a palmer gun, take it in the shower with you(its in the manual).
there isn't one method you should use. use whatever you get results with.