BONDERITE C-AK 4181 L AERO Metal pre-treatment cleaner for rapidly and economically removing strong rust, heat deposits and color, grease and dirt deposits in one stage. BONDERITE® C-AK 4181-L AERO is a liquid, strongly alkaline immersion metal pre-treatment cleaner for rapidly and economically removing strong rust, heat deposits and color, grease and dirt deposits in a single stage. Components made from copper, brass and their alloys are slightly etched and surfaces are left clean and shiny. It prevents quick rusting after treatment.