Clear all furniture and miscellaneous items from the deck. Sweep the deck clean with a broom.
Add a cup of oxygen bleach powder to a plastic bucket. Add at least 1 gallon of water to the bucket and mix the solution. Dip an old broom into the solution and sweep the deck with it to distribute the bleach solution across your deck.
Scrub the deck with the solution using a brush. Start at one end, make your way to the other. You’ll want to wear rubber gloves. Wait 24 hours after scrubbing.
Pour an oil-based sealer into a paint tray. Apply a thin layer of finish across the deck using a paint roller, starting closest to your house and working your way backward. Use a smaller paintbrush for corners and other nooks.
Allow 24 hours for the first coat to dry. Repeat Step 4 to apply a second layer. Again, wait 24 hours before restoring the furniture and walking on the deck.