I take apart and clean my Paasche H after each use. Really not very difficult. I use a mix of window cleaner, simple green, and distilled water for cleaning after acrylics and then a final rinse with Testors Acrylic Cleaner (hard to find now). For enamels, I use regular hardware store paint thinner (mineral spirits).
First I take off the color cup and dump any left over paint, wipe out the cup, and then use either the mix for the acrylics using a small squirt bottle to back wash the stem on the cup. If cleaning up from enamels, I use an eye dropper to do the same. I then fill up the cup with the appropriate cleaner and shoot one or two cups through the airbrush in a cleaning container from Harbor Freight Tools. I turn the paint control cone to different positions while flushing it. After this step, I take the set screw out and take off the tip (cone) and needle and flush both with either the cleaner mix or the paint thinner. Only takes a few minutes and prevents problems in the future.
If cleaning up after shooting Future or clear flat acrylic, I use straight windex followed by ammonia.