Outdoor teak furniture is highly susceptible to mould and mildew growth. Because teak furniture is typically kept outside year-round, it is often exposed to cold, damp conditions which are highly conducive to mildew growth. Teak used for furniture is specially treated and should be given extra care when cleaning to prevent damaging. In order to properly get mildew out of teak furniture, it's important that you use the right cleaners and chemicals.
Use a commercial teak cleaner. For the best results, use only a commercial cleaner recommended by the manufacturer. These cleaners typically come with two substances: one to clean the mildew and another to neutralise the cleaning agent to prevent it from damaging the teak. Use these cleaners according to the directions.
Spray the mildew with white vinegar. Vinegar will naturally eat away at mildew. Let it sit for 30 to 60 minutes.
Wet a sponge with warm water and sprinkle the sponge with baking soda. Spray the mildew again with vinegar and scrub away.
Rinse and dry the teak.
Teak sealer will help prevent future mould growth.
Avoid using teak oil. This actually promotes mildew growth, as it is an organic material.