[Smurf]

Funniest job I did was a conservatory that had a massive bush by the side of it.
I recognised the smell instantly as I had to brush past it and by the time I got home I stank of weed.
Apparently the chap was looking after it for a friend. Yeah right 

Had something similar a couple of years back. leaned into it whilst cleaning a kitchen window and walked round stinking of the stuff for a quite a while. Couple of months later I called to clean the windows and though the plant had gone there were four polish relatives of my customer all sitting round in the garden smoking the stuff and high as kites. I've never had a bunch of people so happy to pay me. They were almost fighting over the privilege. 

Classic...We all like happy paying customers

[kempy]

Killer tree  sap on our lasses car .
Keep telling her to get their earlier and park away from the trees ..... Lol

[M & C Window Cleaning]

You can feel it like light rain when you stand under the offending trees sometimes. Most of the houses I was working last week were surrounded by trees and covered in sap and all sorts of debris from Tuesday' s storm. I used a lot more water last week than I normally do.

[SeanK]

Its very unlikely to be tree sap as it will only come from a wound in the tree, what your taking about is honeydew which
is basically aphid droppings, the best thing Iv found to remove this is adding vinegar to a traditional solution, warm water will help
but it needs to be really hot, unfortunately if the windows are badly covered its a traditional job as your not going to remove it with wfp methods.