Alexandre Souza wrote: You might consider trying to rinse the affected area with distilled water after using the vinegar. (You want to neutralize the affected area as well as possible.) Then take a hair dryer and gently dry the area. I recently found a discarded power supply that was so coated with oily, nasty, soot-like "stuff," that I decided to experiment. I disassembled everything and got my special green soap used for cleaning aircraft interiors and a brush. It worked wonders. I then rinsed the whole pcb (with components) and blew it off with compressed air. Then I dried it with a heat gun (very carefully, as this heat gun could easily ruin everything). I allowed the pcb sit for a few hours, then put it all back together and fired it up without incident. Caution: "Your mileage may vary..." Regards, Robert Greenstreet