How much cleaning is required be fore decorations start ?

Cleaning a wall before painting it can be either a quick job or a major effort depending on the condition of the wall itself. Cleaning the wall before applying a new coat of paint always means more than just a simple washing down with warm water if you really want to make sure the job is done right. Firstly remove any peeling or chipped paint with a putty knife. If the paint is willing to come off without a lot of effort, go ahead and remove, but don't force any paint from the wall that doesn't need to be removed. Sand down raised areas of paint to blend in with those areas where the paint has been removed. Use a duster or dust mop to wipe away areas where cobwebs might have formed. This is an excellent method for cleaning away dirt and dust that could get beneath the paint. Make sure to clean the corners from top to bottom and edges where the ceiling and wall meet. Lastly, use soapy water and then rinse with pure water and then pat dry with a towel. Make sure you have plenty of towels for drying because you want them to be as clean as possible for each section you dry off.

If I have read the question correct there is no need for you to clean before decorating starts. When we go into a customers house we only ask for small objects like pictures, ornaments are moved and then we do the rest, all surfaces are to be sanded down and then cleaned by ourselves by wiping down and hoovering up before decorating starts, I hope this has answered your question

Walls and ceilings in bathrooms and kitchens i always clean prior to painting. Mix up a sugar soap solution wipe away a small area and while still wet wipe the sugar soap off with clean water. I find microfibe cloths work best. You will discover how much cleaning it required by the colour of the sugar soap water at the end