Thanks for all the helpful info. I used Tire Black in the 60's, 70's and 80's.
I have been unable to find it for years. Will try the Kiwi Black Leather Dye.
I live in New Mexico and our sun dulls everything rubber very quickly. I have used some of the spray on products but the sheen only lasts a few weeks and seems to attract dust. Tire Black would last for six months or more. Thanks again. Steve