Berryman offers two different Chem-Dip formulas. One product is intended for general consumer use and comes in 1-gallon paint cans (part #0996). It is safe on for use on plastic, rubber, and most paints and metals but can react with some grades of aluminum and aluminum alloys. If you use this product and have aluminum-based parts, such as a small engine carburetor, please limit soak times to 30-60 minutes per dip with a maximum soak time of 4 hours. The other Chem-Dip product from Berryman is our professional-strength product, which comes in 5-gallon cans (part #0905). It will adversely affect many types of rubber and plastic but is completely safe on all metals. Though 20-30 minutes is a typical soak time, extended soak times are permissible.