sorry, probably been asked a thousand times but whats the best way of dealing with mildew. I have an old yacht and it has some mildew on the inside of the glassfibre and on the sails.
Anything etither strongly acid or alkali will do it depending on the tolerance of the material. In the mildest forms - vinegar/lemon juice or things containing them like glass cleaner at the acid end or baking soda or diluted bleach at the alkali end.
And for interior of boat, cleaning with Lysol (TM) is a good way to clean, remove, and somewhat mildew-proof the surface. Mildew will cause your fabrics to rot, so you should try to keep it at bay.
If the boat is closed up and stored, you can help keep mildew away by putting out lots of mothballs (naptha) - everywhere. Of course, you can't live with them, but for storage purposes, it's not a bad trick. Caution, however - the fumes will taint food, so you don't want it in your food lockers!
For the inside of Sweet Lucy we use dilute household bleech which last for the season. An autumn going over keeps her more or less clean during the winter, too. For the sails, you have to be very careful of anything corrosive, either alkaline or acidic - ie not bleech. I am afraid we cop-out and send the sails for a professional clean during the couple of weeks we take her out of commission each year. I have to say, even this is not always 100 per cent effective in removing the stains, but it keeps the active spores at bay.
I use either dilute bleach for hard surfaces. very weak is sufficient, or B&Q Mildew cleaner for Tents and fabrics .... brings my sprayhood and cabin up fine. There are types of cleaner that are safe on most fabrics available from B&Q and caravan / camping shops.
For the sails this is very difficuklt to remove once stained .... industrial wash may remove most, but you will likely still have osmething no matter what you do. Unfortunately there are not many strong cleaners that you can use safely on sails.
Do you have a product over there called "Damp-Rid"? Its a dry compound chemical that comes in a special container
and it literally sucks the moisture out of the air, and captures the water in a container at the bottom. It is safe to use
and here in Florida many people even use the product in their closets in their homes to prevent mildew.
On boats its used and also we put solar powered or 12V nicro vents.