 But I've never put a sealer or anything on it. Should I do that? I think it would probably be a good idea. There's a couple things I would do. You know, I mean, the reason driveways get mildewy or get blackish is, you know, there's organic material, there's dust and stuff outside, and then you get morning dew, so you got moisture. We always got mold spores and stuff outside, so we get that little coating that's on there.