 They come in water-based and oil-based. The most important thing is to make sure you're cleaning that surface first. You can do a light pressure washing, and there are products. I would stick with the same manufacturer and everything, but, for example, if you go with Olympic, there is an Olympic cleaner that's designed to be used first, and you basically spray it, let it sit on the surface for a while, and then you can rinse it away. Make sure it's super clean, though. That's real important because even though you say it was sanded a year ago, it picks up stuff pretty quickly, including dirt and sometimes even rust.