I take it that the only remedy for the stuff is
landfill?
In my opinion, yes.
it makes a mess when it sticks
black sticky tar.
Can it be baked to restore usability?
meaning 'read once to recover what you can from it'?
yes, to a point.
24 hours at 55degC (and lots of forced air) will take care of
most brands, with the exception of 2400' MRX V. The DEC LCG
archive was mostly silver-label MRX V, but 3600', and the
formulation was different enough that I had OK luck with that.
The thicker tape/binder on the 2400' MRX V is the pits.