Apply the solution to all affected areas with a brush. Leave for 24 hours and then thoroughly rinse and scrub with clean water to remove residues and dead growth. Failure to remove residues may result in discolouration of subsequently applied coatings. Repeat the process if necessary. Do not apply in wet weather. Badly affected areas, or if lichen is present may require the use of high pressure water-hosing to remove all organic growth completely. When the surface is fully dry, apply the appropriate Dulux or Weathershield finishing system. TIP: apply only in dry conditions, above 10°C and when bad weather is not forecast.