I have the Rapid flash blackness used to refresh leatherette parts (including armrest) in my classic car. That has worked very well - but you should not furiously brushing, but note the processing steps as closely as possible. I have to be blackened parts previously oil with a special cleaner and made grease. Then with a very fine sanding sponge minimally roughened and cleaned again. Then the Rapid flash blackness with the enclosed brush evenly and let dry for 24 hours. In conclusion, I have the polished surfaces with a lint-free microfibre cloth - the result is excellent and the portions look like new. Would I do that to me, however, the cost of a sneaker, I do not know!
