Old bullets, useable?

[8X56MS]

Along with the reloading presses, I have been given a LOT of old handgun bullets. Most are in original boxes, but some are showing signs of their age. Two boxes of Hornady .45 Cal 250 grain .452 Colt HP are particularly bad. The metal part is dull and dirty, and the lead that shows at the tip has oxidized.
Are these useable? I did try to clean them in my case cleaner, but while the brass cleaned up some, the lead is still white.
This is NOT loaded ammo, but just the bullets.