First, the tip assembly can be disassembled, and I guess if it is a last ditch effort it's ok, but I don't recommend doing it regularly.. maybe like some of the people here talk about for the 'other' airbrushes... about every 4th or 5th time you could clean it like that... reason is, it's not really a needle you're dealing with on the interior, it's a piece of plastic and easy to mar or bend the tip on (voice of experience)
When I had an aztek I would take off the paint jar, clean it well... replace it with about 1/2oz. of thinner in it (don't use laquer thinner as the aztek is all plastic inside) and blow it out. I would then check the tip assembly and see if it was relatively clean. If the major portion of paint was gone I would then set it inside the jar, and just cover it with clean thinner. I let it sit at least overnight, occassionaly, especially with enamels I would go and swirl the jar to make sure the dissolving paint was carried away from the tip and undissolved paint was exposed then.
After all THAT.... when I took the nozzle out of the jar I would wash it in soapy water then rinse with clear water.. (now yall know why I didnt like to spray enamels at first)
When I was all done I would blow out the tip and maybe run a smidge of thinner through to clear any residual out...
I usually had no problem like this... only once did I have to buy a replacement head... they're not too expensive but enough so I wouldn't want to do it as regularly as you...
At 8 bucks a tip, 7 or 8 tips worth could get you a complete Badger or Paasche set from dixieart.com, 9 tips would buy you one from Michaels with the 50% coupon in the sunday paper... ($76 bucks at Michaels for the 175 set, about $65 on dixie art for the same set, comparable pricing on the Badger 155 and Paasche VL sets for both places.) just something to think about... if you did get one of the two I think you would be pleasantly surprised. I used my aztek and it performed decent for what I wanted it for... now with the Badger 175 it is a whole different world.
Not to push you towards one airbrush type or another, but I think a metal brush would make you happy... no more plastic nozzle tips etc... easier to clean being metal too... shoot some laquer thinner through it and it's clean as a whistle!
---Tom---