Dunno If everyone knows this or not. Lanolyn type hand cleaners (GoJO) will soften up and clean old hard wires.

Interesting!!! When I redid my truck the last time I found a perfect front harness on a old long horn. Shhhh! Don't tell anyone but I got the doors and cab from that truck also. :)

I have used different types of handcleaner to clean off plug wires,hoses and wire bundles and have not had any problems with them.

Yep, cream type hand cleaners are great for cleaning spark plug wires.