Arizona dust and hard water spots build up fast on solar glass, and a dirty array loses output. We clean the panel surface by hand with a soft-water rinse so nothing scratches the glass, and check the mounts and wiring look right while we are up there.
The technician who quotes it cleans it. One point of contact from the first walk to the last.
A specific number for your project, in writing, that does not move after the consult.
Streak-free and stood behind. 5 stars on Google says the work holds up.
Tell us the building, the glass, and the schedule. We will scope it and put a fixed number in writing, for free.