Black mold can appear on wood window trim if outside moisture finds its way onto the trim and you do not immediately dry the wood. If left untreated, the mold could cause permanent stains that ruin the appearance of the trim. A variety of cleaners can remove mold, but they can bleach or otherwise damage the trim. Instead of using commercial products, make your own window trim cleaner that removes mold without causing any damage.
Dampen a nonabrasive cloth or scrubbing brush with tap water.
Scrub the window trim with the cloth or brush until the visible mold spots are removed. Not all visible spots have to be removed in this step.
Pour 1 cup each of tap water and white vinegar into a container or bowl.
Saturate a clean nonabrasive cloth or brush in the water and vinegar solution. Wring out the cloth or shake the brush to remove excess liquid.
Scrub the window trim once more. Be sure to scrub all of the trim that's affected by mold. Wait 15 minutes before proceeding to Step 6.
Repeat Steps 1 and 2 to rinse the water and vinegar solution from the trim. Then, wipe the trim with a dry cloth to remove all moisture from the trim.