I wadded up a light weight cotton paint tarpaulen (12' X 16')which was, unknown to me, slightly damp. It sat in the corner of a house I am working on for a few weeks. I moved it today and discovered that it has lightly molded in a few areas. I spread it out on the front lawn for a while to ensure that it was well dried, then brushed it off with a broom. If it were a smaller item, I would just throw it in the washing machine with a bit of bleach and detergent, but of course it is too large for that. Do any of you folks have any suggestions as to how I may remove the molded areas without damaging the tarp?