Kester 245 "no clean" leaves less residue and less corrosive. Most fluxes (rosin core) leave residue behind, which can corrode things and absorb moisture which promotes things to corrode. So this no clean 245 is the ish, ive had a 1lb roll on my bench for 5 years now. while on solder, I also use Kester 331 water clean which washes off with warm water and an old toothbrush. leaves boards squeaky clean. very nice to use when building up new PCB's. put resistors, caps, IC's, diodes, and headers on the board, then solder, then clean and then use the 245 for everything else (wires, switches, pots, etc..)
here's 12 feet for $2.50
http://www.mtechnologies.com/tools/~Steve
