Some copper water pipe solder fittings have a residue of green gunge around them, due to the finished solder joints not being effectively cleaned after soldering.after new CH installation around 5 years ago.
First Q: What is the green gunge (chemically)? Does the deposit have common or garden name? It must be a Cu compound, but how is it formed from solder flux, copper, solder & propane gas used in the torch?
Second Q: What is the most effective method of cleaning it off, especialy when it has been on the Cu pipes several years? I'd like to get the area around the fittings reasonably chemically clean. I fancy just cleaning with wire wool might leave a residue for the green to re-crystallize on.
Third Q: I thought I had cleaned the joints at the time, so how should soldered work be cleaned to avoid green film formation?
TIA