Especially difficult stains, such as rust and water stains on glass and tar on car wheel covers, pose difficult cleaning problems.
Hydrofluoric acid is extremely potent and dangerous.
It can penetrate thick, calloused skin and even fingernails, causing extensive skin burns and scarring. A major exposure to concentrated HF can bind the body's calcium stores from the bones, causing seizures, bone destruction and death. Inhaling HF fumes can lead to pneumonia. A splash of HF in the eyes can cause destruction of the eye tissues and blindness. Pain is the major symptom.