I just noticed some green corrosion around the shut off valve area under a bathroom sink. This is a new shut off valve that was installed by a plumbing company only around a year ago. Should I have them come out to re do it?
Perhaps excess acid flux was not wiped off. Vigorously wipe the area with a wet paper towel and see if the green deposits come off. If they don't, then rub with a terry cloth rag wetted with hot water. Probably the green will not return.