Austin,
There was an article awhile back in Cleaner Times magazine about bird dropping abatement.
One of the things that surprised me was the mention of hazardous viruses in the droppings. It seems that many viruses are picked up by birds, and excreted out, still in an active state!
Never sweep or cause dust to be stirred up. Wear a respirator and full protective gear.
I cleaned a warehouse front last summer, and first I xjetted some detergent, and washed with very hot water. The building was a brick front, and I had to really put some pressure on before all the droppings came out of the pores of the brick.
There was a couple nests that I found and removed as well. It was kind of funny, the birds were perched on a wire about 100 feet away watching, and within 10 minutes of me being done, they were heading back looking for their nests.
Good luck