I excitedly followed this hot air balloon for 239 miles...
until I realized it was bird shit.
= new reply since forum marked as read
I wash it about once every two weeks, but it doesn't help.
I swear the birds use it for target practice!
Once upon a time I lived in a neighborhood that had many trees and many squirrels living in them. Many of the trees were apricot trees that the squirrels would ravage every spring. My mom came to visit me one summer, rented a red car, parked in my driveway. After the first night, during apricot season, we were going to go somewhere in it when mom noticed that it was all sticky. It was under a couple trees not known for dropping sap.
Then we noticed that it smelled like apricots. And then we washed it off right away. Apricots are a diuretic for the squirrels and they were going to apricot trees next door, they would take a couple bites and throw them around my yard but they would also sit in the trees and crap/pee on things. In this case my mom's rented car, it was literally coated with it... there were lots of squirrels nesting in my trees but they came to the spot over the driveway to nail that little red car. They never did it to my orange car parked in the same driveway.
Thanks for bringing a smile to my face this morning. 
🐦🦜🦅
when you discovered it was bird crap, it must have been very deflating!
