I had some workers at my home climb up the ladder to apply. Being under another roof, I am not sure weather it washed off or not. And yes, I am sure that over time it collected dirt. But, where it was no one could see it from the street.

All I know, is the birds left and never came back to that spot.

The link to the product lists all of the features and how to apply. Also note on the link, that you can buy in quantities less than a case.

Joe