It will be ready to treat with a good sealant in 24 to 48 hours, as long as the weather is good. If your deck's already got sealer on it, there's a stripping treatment that may need to be applied before the cleaning treatment and that costs more. The next step is to use a wire brush to remove as much of the baked-on grease and food that you can. Sometimes it's easier to do this if the grill is hot. Also, a little trick to make cleaning easier next time is to spray on some nonstick cooking spray.
Outdoor Furniture Use a good all-purpose cleaner.
Over the winter the furniture can collect some serious grime. You've probably got the same problem with the plastic lawn chairs that were left out all winter. If you let some of the cleaner sit there for a while, the grime will come off easily with a scrub brush and a hose. If the iron furniture has a lot of rust, you shouldn't let bad cosmetics fool you. All you need to do is take a wire brush and maybe some sandpaper to the rust and the old flaky paint.