a : a thing that is formed by casting inside of a mold or sort: like (one) : a reproduction (as of a statue) in metallic or plaster : casting (2) : a fossil copy of the details of a pure object by mineral infiltration b : an impact taken from an item with a liquid or plastic material : mould They made a mask here from a wax cast of her facial area.

: a mass of plastic subject fashioned in cavities of diseased organs (as the kidneys) and discharged from your body

discard implies the permitting go or throwing absent of something that happens to be ineffective or superfluous though normally not intrinsically valueless.