Anyone know how to remove rat manure stains on vinyl boat seats? My classic runabout sets in a barn while not being used and I always throw a tarp over it to keep the sun from shining in on it in the mornings as the barn faces east with a open front. It also helps keep dust off the boat. It isn't a factory cover which means loose edges for rats and mice to go in. I normally don't cover anything besides the front deck but when I covered the whole boat last time I stored it, it just made mice and rats want in. They manured on the BRAND NEW upholstered seats and its almost like the manure melted and left stains. How can I get these stains out???