We had some orangish Red Mold on a couple cushions that were on top of each other when I put the boat away. We tried vinager and baking soda, 303, soft scrub and magic eraser. Nothing worked. After 3 sunny hot days on the Lake the stains were extremely faded and now after about 12 days of boating this summer the stains/mold are gone. Sun worked the best. I'd try treating with protectant and sticking them out in the sun for a week. If you can get a full week of Sun. It's been raining so much here. I forgot what a complete sunny day feels like not to mention a weekend with no Rain!