A couple of tips: First, I've found that those little gum/butler brushes (wire with short bristles wrapped around, get the straight not tapered) that are used in lieu of floss make great cleaning tools. With my airbrushes (Iwata HP-B and Eclipse CS) they fit all the way from nozzle opening to the paint supply (remove the nozzle first, of course) and ensure that all the paint is cleaned out. Some airbrush designs have a longer distance from the nozzle to the paint reservoir, so they may not reach with all models, but I would imagine they would still be of use. These are great little cleaning tools and are available at most supermarkets/drugstores. Now, keep in mind, this does involve breaking the airbrush down to an extent (removing the nozzle and needle at the very least), but except for quick color changes, there really is no other way if you want to keep the brush truly clean.
I also use the Iwata super lube. After cleaning, I simply apply a tiny amount near the tip of the needle. Seating the needle will push this back and lube the packing washer. This helps ensure a smooth pull of the trigger. I also occasionally lube the trigger assembly itself. I do find that the stuff helps with the performance of the brush. I see if for about $6 for a small tube (a little goes a long way, so it lasts) at airbrush supply outlets (Dixie Art, Bear Air, etc.).
Hope this helps!
