I've never considered it for the top. Use the bestop products or something similar. You have to think about the fact that what doesn't stay on the top is going to streak down your windows. They sell cleaners at any auto parts store. If you want to get it back to a darker color you could try using an upholstery paint. (also available at the ap store)
Oh and BTW I see that this is your first post soooooooooooo Welcome to the forum.