Before you clean it up, why did it grow? Where do you live, humid or dry climate? If you have green grass climate, close all the vents and monitor the %RH when damp outside. Also check space for flooding after heavy rain. If the %RH is +60% for more than a couple days at a time, dehumidify to 50%RH. After you are sure that new mold will not grow, clean up old mold. Check EPA's web site for instructions.