Rubber insulation wire
 

I've found a good source for rubber insulated wire, in 18 through 12 ga. The
smaller stuff is great to replace rotted wire in radios and TV sets. The
larger sizes are great to replace high voltage leads in early TV sets:
http://www.meci.com/ - click on wire, then rubber coated hookup wire.

Several colors are available, but I have used white and spray painted it to
match the original color.

Though the website says 100 ft is minimum order, the printed catalog says 50
ft.