camphorsulfonic acid), the reaction rate can be decreased and the lifetime of the disc prolonged. The residual oxygen can be removed from the substrates used for disc manufacture by storing them under a vacuum or oxygen free atmosphere (e.g. pure nitrogen) for a period of time (hours to days). Alternatively, an oxygen scavenger (e.g. iron(II) salts, tin(II) salts, or organometallic compounds) can be added to the polymer formulation, reacting with the oxygen present in the polymer matrix in shorter timeframe than the hydrolysis of the blocked leuco dye takes. The reaction timing can be further controlled by addition of other substances. As the diffusion rate of oxygen through the polymer layer is more or less constant, a supply of suitable antioxidants (e.g. organometallic compounds) which react with the oxygen preferentially to the leuco dye leads to gradual depletion of the antioxidant compound. Only after the antioxidant is consumed, the leuco dye starts being oxidized, achieving the period of delay of the reaction onset, followed by a rapid reflectivity degradation. Stannous ethylhexanoate can be used here as the antioxidant organometallic. Various resin-soluble tin(II) and iron(II) compounds can be used, e.g. chelates and fatty acid salts. Other usable compounds are e.g. hydroquinones, alkylhydroxylamines, dithionates, reducing saccharides (e.g. glucose), α-hydroxyketones (e.g., hydroxyacetone), substituted boron hydrides and silicon hydrides. The oxidized dyes in the expired discs absorb primarily at the wavelength of the current diode lasers (red, 650 nm) used in the DVD players. However, the new generation of DVDs is designed to use blue lasers at 450-460 or even 405 nm, for which the methylene blue is essentially transparent. While SpectraDisc did not take this in account, the Flexplay discs incorporate a red color filter, blocking blue lasers from reading the disc, expired or not. Acridine Yellow can be used for this purpose, together with 9,10-bis(phenylethynyl)anthracene, and a scale of different azo dyes, aromatic hydrocarbons, and other dyes. The dyes can be added directly to the polycarbonate resin the discs are made of. Additionally, other methods of the disc degradation are proposed to be deployed together with the primary one; the concern of the technology developers here is that while the dye oxidation mechanism prevents the disc from being read by current consumer technologies, the information on the disc, recorded in the pattern of the pits in the reflective layer, remains intact and could be recovered. One of the methods is to make