Wet Storage Stain On Galvanized Metal: Causes And Prevention

Finish American Galvanizers Association


If you’ve noticed dark spots or streaks on your galvanized metal, you may be dealing with wet storage stain. This discoloration can occur during storage or transportation of the metal, and can be a frustrating and costly issue to deal with. In this article, we’ll explore the causes of wet storage stain and provide some tips for preventing it.

What is Wet Storage Stain?

Wet storage stain, also known as white rust, is a type of corrosion that occurs on galvanized metal when it’s exposed to moisture or high humidity for an extended period of time. It appears as a powdery white or gray film on the surface of the metal, and can eventually lead to pitting and other forms of damage.

Causes of Wet Storage Stain

Wet storage stain is caused by the formation of zinc oxide on the surface of the galvanized metal. This can occur when the metal is exposed to moisture or high humidity, which causes the zinc to react with the oxygen in the air. The resulting zinc oxide can then react with more moisture to form zinc hydroxide, which appears as the powdery white film on the surface of the metal.

Preventing Wet Storage Stain

The best way to prevent wet storage stain is to ensure that your galvanized metal is stored in a dry environment. If you’re storing the metal outdoors, make sure it’s covered with a tarp or other waterproof material to protect it from rain and humidity. You may also want to consider using a dehumidifier or other moisture-absorbing product in the storage area.

Cleaning Wet Storage Stain

If you’ve already noticed wet storage stain on your galvanized metal, you can try removing it with a mild detergent and a soft-bristled brush. Be sure to rinse the metal thoroughly with clean water and dry it completely before storing it again.


Wet storage stain can be a frustrating problem for anyone who works with galvanized metal. However, by understanding the causes of this type of corrosion and taking steps to prevent it, you can help ensure that your metal stays in good condition for years to come.