Clara,

          The problem with my airbrush sticking seems to be with the
          tiny rubber O-ring.  I take the airbrush apart so that ring
          is accessible, squirt a little graphite powder in the area,
          put the pieces back together, then move the lever up and
          down a few times.  It works like a charm.

          I got the graphite powder at a hardware store; it was cheap
          and came in a little plastic tube.  It's used to lubricate
          locks.  Probably the dust from a mechanical pencil sharpener
          would work, but it might not be as fine or it might have
          larger grit scattered in.

          Good luck.

          Lynette
          Morrison Planetarium
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