Harris Product Group Stay-Clean Paste Soldering Flux Stay-Clean Paste soldering flux is superior flux for most metals including copper, brass, bronze, steel, stainless steel, galvanized and monel (not recommended for aluminum, magnesium or titanium). Stay-Clean Paste soldering flux meets commercial spec. A - A - 51145C, Form A. Stay-Clean Paste soldering flux should not be used for electrical or electronic applications. . Pack of 1