On grooved asphalt runways at LON airports where rubber build up reduces friction levels I believe high pressure water is the method used. Normally carried out a couple of times a year at the TDZ areas. Chemicals have been trialled but the water method is I believe still the most effective.
It is fairly costly because of specialist equipment needed but for a couple of times a year to maintain good friction levels and a safe running surface then cost is not an issue.