Another question for the experts.

I'm in the process of reviewing a teaching slide set which includes
some slides which are decades old.  Many of the slides show
fading of the hematoxylin at the edges, while the eosin staining
looks normal.  Is this an oxidative change?  Can it be cured?

Thanks in advance for your experience and comments.

Hal Hawkins
UT Medical Branch, Galveston, TX