To do this, you'll need a quality silicone sealant, ideally one labeled for bathroom use like the GE Supreme Silicone Caulk for kitchen and bathroom. Other essential items include a caulking gun ...

Use a sponge to clean and rinse the sealant, then thoroughly ... all mould stains are gone and your bathroom is sparkling clean again. How to prevent silicone sealant mould in the future.