I'd like to hear from those who have used Maxwell's technique of detecting fuel tank leaks. Specifically.. 1) What type of soap did you use? It seems like you'd need something heavy that won't run off. 2) How did you put the plastic over the inspection panels? Maybe just slather petroleum jelly and set it over the panel? 3) How did you seal the vacuum attachment around the filler?   I've always had success with a casual application of sealant in the general area of a fue