Yeah I was surprised to start seeing comments on this feed again, but the advice from all is well appreciated.
My resolution on this was to not worry so much about it since they’ve been happy with my work.
Toilet bowl cleaner is an interesting thought, I love the creativeness behind what people come up with. However, with the risk that you mentioned, I’m not sure that would be my best method to go with, at least not on this job. I can always inspect the ground level windows from the outside but I have no access to the inside of any upper levels. I will look into this, maybe a diluted solution would be safer? Idk, it sounds worth checking out.
Plus, I guess you would have to feed it through the hose with a pump right?? I wonder how a pump would handle that type of chemical.
Thanks for the feedback.