I painted the aluminum siding because I got tired of the color about 10-15 years ago. There is nothing to it. Wash with TSP, use a high quality primer and paint. I have found that the best paint comes from specialty paint stores, not home centers and especially not mass marketers who also sell tires and t-shirts--if you get my drift. The only thing I would alert you to is that once you start with regular paint, you will have to repaint every so often. The time span depends on paint quality, climate, etc. but I figure every 10-12 years for our place.