Deteriorating cables

First thing that I've noticed was that all the cables to relays were deteriorating.  Interestingly this doesn't only happens to me. I saw bunch of posts on Firebird forums, where people were describing the same issue. Seems like a common problem that happens over time.  What I did so far is I cleaned them all from old grease, take of each cable from the connector and put shrink tubes.  It's hard to say how good the cables looks like under the protection cover. I will try to start the engine first and if I will be successfull at some point I want to track these cables and hopefully replace them fully.