PROBLEM TO BE SOLVED: To enable a colorant component to be recovered without fail from the substrate of a disk-like information recording medium comprising the substrate and a colorant layer a reflective film and a protective film laminated thereon by separating the substrate from the reflective film and bringing the substrate into contact with a soln. capable of dissolving the colorant layer. SOLUTION: The substrate is separated from the reflective film pref. by the exposure to ultrasonic waves in a medium. The colorant layer is removed e.g. by dipping in a solvent capable of dissolving the colorant or by spraying the solvent. The solvent used here is pref. the one which does not affect a polycarbonate constituting the substrate examples being alcoholic solvents 12-ethylenediol glycerol Cellosolve solvents and hydroxyketone solvents. Thus the resin of the substrate is made reusable as a clear resin. In recovering the colorant it is pref. separated from impurities by filtration.
An excellent method for removing impurities from the optical disks.