btw, you need a clean tire surface to get good application of dressing.
i use this or this to clean the sidewall real well to first remove release lube and the mounting lube tire stores use to mount the tires.
motor spray/nitro cleaner like this... there are others out there. spray into rag (not paper towels) and rub the surface gently till fresh rubber.
Amazon.com: HPI Racing 74116 Nitro Car Cleaner, CA Compliant: Toys & Games
Goof Off FG659 Heavy Duty Spot Remover and Degreaser, Trigger Spray 22-Ounce - Amazon.com