Took some time last Monday to checkout an issue I had a while back. The fusible link from the starter to the horn relay needed some attention. 
I dropped the starter and uncovered the wires. Black tape and plastic wrap hid what I found. 

Here is where the fusible link was suppose to be attached to the wire running to the firewall connectors and the horn relay

Here is the fusible link, I don’t think this was factory installed. Probably from a previous owner.

here is the connector that I cut off the above wire to repair the connections.

Yup! Bubba was in there. That green stuff is NOT suppose to be there.  It has no doubt migrated down the wire where it can't be seen. Toast, from what I can see. Wire is cheap. 

Good catch! Be sure you have some sort of fuse, or other protection on that wire....sure don't want a major fire taking place! 

Wow that is ugly. And dangerous. I'm sure you will take your time and fix this correctly. I  hope whatever burnt the link is no longer an issue!