Add the alcohol and essential oil to a spray bottle. Shake the bottle to combine the ingredients.
Add the vinegar to the tea tree solution.
Spray directly on mildew, let rest, then wipe clean.
Notes
100% vinegar may be used in this recipe without the addition of the essential oil (and rubbing alcohol). I keep tea tree in my cleaning toolkit for homemade cleaning and beauty products, so I add it to this spray due to its antibacterial and anti-fungal properties. I've found that about 60 drops of tea tree is best for the problematic mildew areas in my home.Vinegar shouldn't be used on some surfaces, like marble and granite.