Aluminum/25-50% nitric acid, by volume **A 3-6% H2SO4 sol'n. heated to 70-80'C is commonly used for removing heavy scale. Stainless Steels/1-2% H2SO4 and 0.1% HF, 1-2 min Copper, Copper Alloys/5-15% H2SO4 or HCL, by volume Steel/5-10% H2SO4, by volume, 15 s-2 min** Metal Substrate/Common Acid Solutions* Zinc Die Castings/0.25-0.75% H2SO4, 20-30 s High-Carbon Steel/Anodic treatment in 20-65% H2SO4, 15-40 A/dm^2, 1 min *All solutions at room temp