The Polane paint is about $50.00 a gallon and should be used once it is opened. It is better to just clean your old cord if you can.
Sandman.com and phoneco both advertise cord cleaners.
There used to be a place in AK that would paint a phone for you. The lady was a retired bell employee that used to paint phones. She charged by the piece, but wouldn't paint until she had 50 pieces of the same color.
A 500 set is 4 pieces, housing, handle and 2 caps.
Jim S.