I've got old BASF and Memorex tapes (20 years +)
that are fine
You are extremely lucky. Memorex early 80's tape is the worst
stuff I've ever had to deal with, esp MRXIV (red label) andn MRX?? (light gray)
If you have anything you care about, get it off of those reels ASAP.
It is classic "sticky shed syndrome". The binder becomes sticky and glues
the layers of tape together.
If you're interested in the details, you might want to try to find a copy
of "Tribology and Mechanics of Magnetic Storage Devices" by Bhushan esp
the chapter "Role of Chemical Properties in Magnetic Tapes".
---
Magnetic tape media has become the bane of my existance :-<
The sooner that I can get rid of every mag tape I own, the better...