Sweep the entire surface of the vinyl deck with a broom to remove all loose debris.
Look for any stained areas or instances of mildew. Fill a spray bottle with a mix of equal parts of water and white vinegar. Spray problem areas until they are saturated. Allow the mixture to sit for five minutes.
Fill a bucket with 1 gallon of water and 2 to 3 tbsp. of liquid dish soap. Stir the mixture until suds form.
Insert a long-handled scrub brush into the soap mixture and apply it to the vinyl deck. Scrub the deck with firm back-and-forth motions to dislodge any dirt, stains and mildew.
Screw a sprayer attachment onto the end of a garden hose and spray the deck with water to rinse off the soap mixture. Continue rinsing until no more bubbles are visible on the deck surface. Allow the deck to dry completely.
Examine the caulk in all connection points such as on stairs and handrails. Scrape away any loose or damaged caulk with a caulking tool and apply a thin bead of clear exterior-grade caulk to any seams to seal them.