Just a little snippet here to debate:
Question: What is the right way to clean a very dirty wall. From the top down or the bottom up?
Answer: Easy from the top down, well is it?
Ill explain. My answer is based around smoke damage really, however we have found it to be true on all different types of greasy walls not smoke related.
We were taught that it was always from the bottom up. The reason for this is that if you start at the top the solution will almost always try to run down the wall.
In doing so, the resulting streaks set the dirt below before you have a chance to get to it. When you come to wash the area below you often find that you cannot remove the streaks.
If you wash from the bottom up, any residual "runs" hardly effect the wall because it has already been cleaned. I know dirt can still run down, but it never seems to set on a cleaned surface.
Now the times both I and my superiors have held competitions with the staff to prove this in the field have been numerous with almost all being converted to "up washer", which was the point, although I will agree it still feels awkward.
Its common for people not to agree so I don’t expect any here to either. What I will say is if you haven’t tried it then do, you will be very surprised at the results.
We use Strongarm or Heinkel Power Clean in different dilutions for all wall and ceiling washing (cuts through anything).