I found 1/4 inch all cotton cloths line rope at Mills Fleet farm.
3/4 cup saltpeter too two quarts water works ok but less will also work, i cut the time i let it soak in it too 3-4 hours last time.
Side note:
Lay the cord flat to dry like in an disposable pie tin or similar .
Saltpeter source.........
http://www.skylighter.com