I enjoy riding "Show bikes" and found Westley's Bleche-Wite works great when used properly.
Never spray it directly on dry tires, and never allow it to dry on the tire.
I spray the tires liberally with water and then give 'em a quick, light spray of WBW. Brush with nylon bristle brush and immediately rinse clean.
Product can also be sprayed on the wet brush instead of the tires, but tires still must be watered first.
Works better than a charm, and never caused any problems for me... other than having to occasionally defend comments that I must never ride my bikes,

which I'm ok with!