What causes VCR tapes to degrade? Can they be saved.

[89ARIES]

My family has a collection of home-recorded VCR tapes dating back to 1990. Many of them are starting to have issues. Everything from juggling picture to sound distortation to bad tracking.
Was watching an original 1990 Desert Storm News Hour when the tape starting to shake. In the beginning of the film is a rare TV clip of me at age 9 in a veterans cemetery. The darn picture now
begins with jiggling and sound distortation. Also, we have 4 tapes from the 1980s that run okay, then we have tapes as new as 1998 that are a basket case. I just don't get it. Can someone please
add to this thread as a scientific discussion about why these tapes do what they do and how they should be stored? I am going to be buying a DVD converter as soon as possible to copy this stuff.

[Baron]

Probably doing the conversion is the smart thing to do.

But, have you tried just cleaning the tape head in the VCR machine itself? It can get coated with the finish/dirt/oil/etc from the tapes being played. You can- or at least used to be able to- buy cartridge tapes that were designed just for that purpose. You just put a little alcohol on the tape, inserted it, ran it for a few seconds/minutes, let the alcohol dry off of the head and start using it (basically just follow the instructions that come with the cartridge). I used it many a time on my machine in the past. It sounds like a dirty VCR head could very well be your problem.