Airbrush Cleanup
Many airbrush problems are caused by improper cleaning methods. The dried paint can result in clogs that make it impossible to achieve proper performance.
You can use the same thinner to clean the airbrush, or solution of common chemicals. For acrylic paints, isopropyl alcohol (from the drugstore) mixed with water makes a great cleanup-thinner. I use this between colors.
For final cleanup after acrylics, I like to soak the airbrush parts in a 50:50 Windex: water mixture.
If just resting the airbrush between coats, I'll close the nozzle to prevent dried paint on the tip.
If changing colors, pour out the excess paint into a waste container, wipe out the cup or bottle, then spray the thinner mixture through the airbrush.
Spray more thinner mixture until it comes out of the brush clear. Turning the brush upside down (siphon feed color cup) while spraying helps clear out the last of the thinner.
At the end of a spraying session, I like to disassemble the nozzle and needle and soak them in cleaning solution.
Rub gently with cotton swabs, then wash in soap and water, leaving to air dry. Don't forget to clean the color cup or bottle.
Note that siphon bottles (or cups with caps) will have a small hole on top to allow atmospheric pressure to work.
This hole can get clogged by dried paint during spraying, so keep an eye on it.
Proper attention to cleaning will go a long ways to ensuring an enjoyable airbrush experience. Now find something and go paint!