Apply a paint stripper to the painted areas on the deck. Lowe's home improvement store recommends using a paint stripper that washes away with water for the easiest cleanup. Ace Hardware suggests picking a paint stripper that sprays on for the fastest application. Home improvement stores also sell paint strippers that users can apply with a paintbrush.
Allow the stripper to sit on the deck for the amount of time recommended on the paint stripper instructions.
Put gloves on. Paint strippers contain harsh chemicals that can damage the skin.
Scrape off the paint stripper and as much of the old paint as possible using a putting knife or other type of flat metal scraper. Lowe's suggests slightly dulling the edge of the scraper to make sure it does not scratch or gouge the wood.
Scrub off any extra paint with steel wool soaked in the paint stripper.
Rinse away the paint stripper with water.
Sand off any stubborn paint spots with 120-grit sand paper, which has a coarse texture that will smooth the wood and remove any paint that has soaked into the open wood grain.
Sand the deck again with 220-grit sandpaper to make the deck smooth enough for repainting or refinishing.