I give mine a good scrubbing every couple of weeks with some lemon SoftScrub and a green 3m pad. Don't forget the elbow grease.
After scrubbing use 409 and a (paper) towel to remove the cleaner. Leaves range top clean and shiny.
"I must say as to what I have seen of Texas it is the garden spot of the world. The best land and the best prospects for health I ever saw, and I do believe it is a fortune to any man to come here."
Davy Crockett, 1836