The subject of tire cleaning came up during last year's DaVols Cup series. I had noticed that a top running car in the earliest races had dropped to the bottom of the finishing order, since we were hosting two races I volunteered to inspect the car before the second race and I noticed that the tires were glazed, in fact they had almost no grip. I used contact cleaner to remove the glaze and the grip was restored. I do not think that any of the other cars had the same problem, but I am not positive about.
It is best to condition the track with the tires that are going to be used in the proxy series and to avoid running any other type of tire until the proxy racing is done.
Different types of tires require different cleaning methods. Sticky tape will remove ordinary dust from any type of tire, but it will not remove a glaze from rubber or urethane tires. Perhaps a standard cleaning method should be mandated in the rules.