My hot tub sits under a tree that has become host to Wooly Aphids the last couple of years. They feed on the leaves and secrete honeydew - a sticky mess that covers everything and molds quickly when wet. Here is a picture of my 15-month-old cover following a couple of weeks worth of rain, then another picture after two hours worth of scrubbing with soap and water followed by a liberal coat of HotSpring Cover Shield. I love it when things clean up nicely! Honestly, I didn't think the stuff was going to come off without soaking the whole thing in bleach.
