Insect repellent
BANG! We have a winner.  

That is the result of the cable coming into contact with 
Aerogard.  The stuff we spray all over ourselves and the kids!  
 
  
 
The cable gets stored in a small plastic container along with, amongst other things, a pump spray bottle of Aerogard.  Needless to say the bottle leaked and the cable sat in it.  I worked out that it was probably in contact with it for a day or two.  But still... WOW.
Obviously Bushmans has the same effect.
LJ
PS Where should I send the prize too Mike?  (It's a couple of unused cans of Aerogard  

 )