Yeah, i bought a huge put of the solid flux, and ive had it for about 2 years, and its still near the top LOL, but yeah what I do is either rub/dip the wires into it or use tweezers and wipe them, only problem, if it got on your hands, its so hard to get out, also since its solid, i dont like using it
Then theres a white paste that I got recently, ALOT easier and nicer to use, just harder to find in stores, same price though, you can easily dip and rub the wires into it, or put it on tweezers and wipe it onto the spot
And the pen, i dont actually own one but i have borrowed one, i love them, they make working on smd boards (Like changing LEDs on PSP motherboard) alot easier, but you cant really use them on led mods on wire, since you cant really get all the wire
conslusion, the whitesh paste is the best to get to be honest, i got mine off dealextreme aswell, been using it for ages