Vinegar would also work well, use straight white vinegar in a spray bottle, and treat the molded area about once a day for 5-8 days. Watch the area to see if there is any mold growth, and after a couple weeks, I would say it is fine to use some type of sealer, varnish, or paint. I recommend a polyurethane type varnish. It will seal the wood pretty good.
2/9/13 at 8:41pm