aluminum, brass, copper, chrome, gold, lead, nickel, silver, titanium, tungsten, solder or solder points. Metal Rescue™ will clean oils and some contaminants, and will not damage any of these metals. It is designed mainly to remove iron oxide (rust). In addition, Metal Rescue™ will remove some oxides from copper and certain aluminums.

The black is from iron oxide II, often referred to as black oxide. Black oxide is a corrosion inhibiting film that is a more stable state of oxidized iron. It is not detrimental to the metal surface and is only cosmetic in nature. It can form on certain steel alloys and high carbon steel when left in Metal Rescue™ for longer periods of time. For these metals, reducing the time that the part is immersed in the liquid will minimize the black film. Much of the black oxide film can be removed simply by rinsing with mild detergent or wiping with a cloth. Also, it is best to remove it immediately after removing parts from Metal Rescue and before the parts dry. The black oxide becomes more difficult to remove for parts that have soaked for long periods of time. It is best to soak rusted parts only as long as needed to remove the rust.

When exhausted, the Metal Rescue™ bath will turn completely black and rust removal rates significantly decrease. The specific gravity will change from 1.02 to 1.06. There are many ways to measure specific gravity. One way is to use a hydrometer. They are easily available and cost between $5 and $15. They are commonly used for home brewing and wine making, and also used by people who keep salt water aquariums. Additionally, most manufacturing facilities with labs or chemicals have several ways to measure the specific gravity of a liquid.