Found this on another forum-
"Bronco vehicles equipped with the hard top roof option are compatible with traditional drive through car washes. Plastic surface conditioners and spray (liquid) wax/detailer products may also be used for care and maintenance.Avoid cleaning the hard top exterior surface with power tools/buffers, rubbing/polishing compounds and paste waxes/polishes as this could scratch or damage the surface. Cleaners that contain alcohol and other strong solvents such as toluene or acetone must never be used. Using those types of cleaners may cause unrepairable damage to the surface of the hard top. In all cases, verify compatibility in an inconspicuous location prior to broad application."
I've just been cleaning mine with soap and water when I wash the whole thing. I think a once or twice a year liquid conditioner product might be good if I feel it looks like it needs it. I guess Aeropsace 303 spray is good