The 1-gallon and 5 gallon Chem-Dip are two different products.  Our professional-strength product comes only in 5-gallon cans (part #0905) and larger. 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 without damage to metal surfaces. The other CHEM-DIP product from Berryman is intended for general consumer use and comes in 1-gallon paint cans (part #0996)., which is the industry standard for this type of product.  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 any aluminum-based parts, please limit soak times to 30-60 minutes per dip with a maximum soak time of 4 hours.