Vanadium stains should be removed prior to cleaning with hydrochloric acid. Vanadium stains are yellow, green or reddish brown discoloration commonly present
on newly laid bricks.
Steps for removal:
- Take sodium hypochlorite, the active ingredient in household bleach and pool chlorine. This is a a good treatment for mild stains.
- Sodium hydroxide, more commonly known as caustic soda is also a good treatment. Take 21 ounces per gallon of water.
- Spray or brush solution onto a dry wall. When stains disappear rinse the wall thoroughly.
- Oxalic acid is the most common removal method. Mix 2.8 to 5.6 ounces of oxalic acid per gallon of water. Apply mixture to dry wall. When stains disappear, neutralize the acid on the wall with 2 ounces of washing soda per gallon of water. Do not rinse off.