I soak mine in everclear. (PGA, Golden Grain, 190 proof alcohol) for a few hours then rinse in hot water.
blow the rest of the water out and drip.
Get that pack of cartomizers. They are so cheap, I just throw them away when the gum up. I get a week or so out of one.
The ego tank systems are praised by some and cursed by others. I've never used them, but I've heard that they can leak.