If you have a small area or smudge that you need to touch up and only have a siphon-feed airbrush, try turning the brush over. Now, the suction tube acts like a small gravity-feed reservoir. I fill the tube using a dropper and lower the air pressure so I get a fine mist to cover a mark or blemish without applying too much paint.
Tip submitted by:
Rusty CarsonBethlehem, Pennsylvania