A lot of old master tapes self-destructed due to bad chemistry. The binder material used to adhere iron oxide particles to the tape backing was, in many cases,

A lot of old master tapes self-destructed due to bad chemistry. The binder material used to adhere iron oxide particles to the tape backing was, in many cases, slightly hygroscopic; over time, the binder absorbs water, breaking down that adhesion and causing the oxide to flake off when the tape is unspooled. The only known remediation measure is to bake the tape at low temperature, which will temporarily reduce the moisture content sufficiently to allow the tape to be played back and re-recorded. https://en.wikipedia.org/wiki/Sticky-shed_syndrome https://en.wikipedia.org/wiki/Sticky-shed_syndrome