I've had mine for 12 months now, no problems except for a part lost down the sink....
While the manual says dont break it down, there is nothing wrong with doing it (cept doing it over the sink 
). The tips should break down to three parts the outer shell, part, both plastic and depending the type of tip is if the needle is plastic or metal.
I just use a small container filled with applicable thinner and paintbrush to wash the parts until they are clean, dry careful and then slip the midle part into the out side and then needle in last (to undo remove the middle from outside then remove needle). As long as all is done with care its an unremarkable process. I do about every two to three weeks, or immediate if I stuff up and dont thin the paint enough (or wrong thinner).
Andrew
Edit in - PS me bad, there is a spring that wraps right over the needle as well, remove this last when stripping , replace first when re building