As you may already know, Berryman offers two different Chem-Dip formulas. Professional Chem-Dip product is only available in a ready-to-use fashion in 5-gallon cans as part #0905. It is completely safe on all metals for extended soaking but it will adversely affect many types of rubber and plastic. (One of the primary ingredients in this version is the same active ingredient that gasket removers use.) Our other Chem-Dip product (part #0996) is intended for general consumer use and is available only in 1-gallon paint-style cans. It is safe on for use on plastic, rubber, and most paints and metals, but it can react with some grades of aluminum and aluminum alloys. If you use this product and have an aluminum-based carburetor (which is quite common), please limit soak times to 30-60 minutes per dip with a maximum total soak time of 4 hours.