Folks, I have thrown away several sets of Coker's for various reasons. Call Diamond Back, talk to James. I have done business with them for years and have their tires on my 49 Special Deluxe with Beauty Rings...a few bucks per tire but makes all the difference, on my 36 F*rd and on my 55 Nomad, and those are custom redlines.
Only use Simple Green for cleaning and spray that on a clean white terry cloth or micro fiber towel, not directly on the tire. I also suggest using one cloth per tire so you are not just moving dirt from one tire to another.