Good day Matti, I would lightly crape the mold off then wash with brine made with 3% salt and 1 TBS of vinegar to 1 cup of water. If the mold is persistent you may need to dab with some spots with straight vinegar. If you are using an aging box you may need to open it every other day for air circulation. Maybe some one with more rind development experience can chime in here.