I've always used the proper stuff at work, it's just at home I'm a tight git use the soapy waterJust buy proper leak detection fluid. It’s not expensive and safe with gas and fittings.
I said someone would be along in a minute to say it was a bad idea and you didn't fail me , I never said it was a good idea just what I have done in the past and just for the record I've never had any corrosion of the brass fittings. I've done it for other people when they have put their regs on dry and had a leak but after I re-did it with a bit of washing up liquid the leak then stopped, @Brad93 what would be a better substance to use then ? I'm always willing to learn and change my habits.That’s terrible from a contamination point of view and from a corrosion point of view. Alkaline fluid on brass.