a : something which is fashioned by casting within a mould or type: for instance (1) : a copy (as of the statue) in metal or plaster : casting (2) : a fossil replica of the details of the purely natural object by mineral infiltration b : an perception taken from an item using a liquid or plastic compound : mould They created a mask from the wax cast of her face.
: a site mass of plastic subject fashioned in cavities of diseased organs (because the kidneys) and discharged from your body
discard implies the permitting go or throwing away of something which has grown to be useless or superfluous even though generally not intrinsically valueless.