For example Hydrochloric acid (HCl), nitric acid (HNO3), Phosphoric acid (H3PO4); HNO3 is traditionally used to remove uranium; addition of Hydrofluoric acid (HF) greatly increases DF. The acids used for decontamination include hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid. Their main purpose is to attack and dissolve metal oxide films and lower the pH of solutions to increase solubility or ion-exchange of metal ions, and can be used on almost all metal surfaces except reactive metals such as zinc.