Hi @BrieD,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
To clean and remove the mould, start by putting on a mask and gloves to protect yourself, then use a mould cleaner such as Selleys Rapid Mould Killer Remover and scrub it with a brush like this Oates Soft Grip Grout Brush to get into the aluminium tracks. Once the mould has been agitated, use some rags or paper towels to wipe away the liquid and mould and dispose of it.
Black mould grows when moisture is allowed to sit, so to prevent it from returning, you'll want to ensure the door and window frames are not allowed to stay wet. Check for condensation in winter and make sure windows are closed when it rains to prevent that sitting water. Keeping the air flowing around them when possible and wiping up any excess moisture will help prevent it from growing.
Let me know if you have any further questions.
Jacob
