Tony,
What i use on my black vinyl convertible top are 2 of Meguiar's products.
After it rains here in Phoenix, the car usually gets a coating of desert dust, as the rain dries.
First I use Meguiar's M-39 Heavy Duty Vinyl Cleaner, usually 2 applications to get all the dust stains out of the weave pattern, then one application of M-40 Vinyl and Rubber Cleaner/Conditioner. In both cases I use a microfiber towel to apply and a clean microfiber towel to wipe off any excess after I do the whole top. I change microfiber towels as needed, and use separate ones for the M-40 applications.
To detail the car before a show I just use the M-40 and go over the vinyl once.
Mark