First wear gloves. I would put 1/4 cup bleach to 5 gal bucket of water as warm as you can stand. Get rag/soft cloth and dip into mixture. Wring rag and wipe down case thoroughly. Do this several times. You don't want the rag to be dripping wet. You may have to use a scrub brush and gently brush through to get to corners. Then wipe again. Take dry rag and wipe again to get any excess moisture off of wood. Let dry outside and preferably in sunny area of yard. Should be stored in area where circulation of air is good. that is how I have handled mold on wood. When done, I usually wipe down with Murphy's Oil soap and then a good oil. Others on QB I'm sure will have other recipes for mold eradication.