Good soap/solution for presoaking?

I’m not conerned about slip. We’re 99% residential with constant new clients. And every once in a while, you get the house with windows that haven’t been cleaned in 20 years.

Is there something other than acid that you could just put on a scrubber and pole to just presoak and help get some of that really nasty stuff off? Obviosuly the typical dish soap isn’t great at this; it can help, but not a lot. Maybe amonia or sonething? (Outsides only)