Lead is still widely used for car batteries, pigments, ammunition, cable sheathing, weights for lifting, weight belts for diving, radiation protection and in some solders.
A good way to distinguish lead from other non-ferrous metals is by filing it. Lead will be soft and will file easier than aluminum and stainless. It is also generally heavier than aluminum and stainless.
Separate lead acid batteries from regular lead pieces as they are paid at a different rate.