Does carb clean loosen paint like brake clean does? I need to check for vacuum leaks but I don't want to use anything that will discolor or loosen the paint. What about soapy water? Will that bubble up around a vacuum leak like it does around a tire leak? Probably not since there would be vacuum instead of outward pressure. I don't have a cutting torch so oxy/acetylene is out. I do have a small propane torch if that would work.