Remove solid stains from a deck using a chemical deck-stain remover. Avoid sanding pressure-treated wood decks as the process releases harmful chemicals. If planning to apply another solid stain to the deck, there is generally no need to remove the previous stain before proceeding.
Regardless of the procedure you select, begin the process by cleaning the deck. Attach a scrub brush to a broom-length handle, and scrub using a trisodium phosphate solution. If you choose to use a pressure washer to clean the deck, be aware that it has the potential to make existing weathering of the decking material worse by splintering boards.
Use a paint scraper to remove any loose or peeling stain from the surface. The scraper also helps to locate any loose nails or screws. Reset them as you proceed.
Before applying the stain remover, water the landscaping surrounding the deck to protect it from the chemicals. Cover nearby shrubs and grass with plastic drop cloths for further protection. Protect siding with more drop cloths.
Apply a thick coat of the stain remover to approximately 20 square feet of deck surface and allow it to stand until the stain softens. Use a water hose and scrub brush to remove the loose stain. Repeat the process to strip the entire deck. Allow the surface to dry thoroughly before applying another finish.