I keep my boat at the marina in a boat slip. There are a lot of ducks and geese in the area and they constantly shit on the boats. Mainly the swim platforms. I have seen multiple solutions including: alligator head, Owl, flags and sparkles. My first question is which have people found to be most effective?
Second question is: The duck / goose poop seems like it leaves a stain on the gator step material on my swim platform. Any recommendations for getting this out?

Thanks in advance