CAUTION: The ammonia present in some soaps and detergents can react with brass fittings and cause such fittings to crack and leak after a short period of time.
Therefore, DON’T use dish washing liquid. I’ve found the best to be about 10% Truck Wash mixed with 90% water in an atomiser spray bottle. If you are still in doubt that the soap solution may contain ammonia, rinse all connections thoroughly with fresh water as soon as possible after the application of the soap solution.