actually, its not a bad idea.. but i use air brush propellant for cleaning the caps, after soaking them in paint thinner..
If you're gonna soak em in thinner, after you do that, grab a can of air duster, like for keyboard cleaning and what not, and stick the cap on the little hose, fits perfectly. Blow some air through it and you're good to go. hell you could even use wd40 or anything that comes with a straw, they all fit into the stem of the cap. wooo
i bout a bag of 125 different caps like a year ago...........(which i STILL use). All u have to do is bring them home and throw them in some soap water then blow them out.........easy as that. dont gotta get all technical with the paint thinnners n shit.