It is important that you let your homeowner know that in order to do your job, they have to let you, the trained professional, do all of the cleaning. When I have a homeowner that wants to do bits and pieces of their cleaning, I simply educate them as to why that is not a good idea.
In order to be able to guarantee your work for order, you must know how each and every item has been handled to ensure proper cleaning and deodorizing. You cannot guarantee anything that you do not handle yourself. And if those items that you did not handle are put back into the house and mixed with the items you did clean, they could re-contaminate the entire house if they weren't processed correctly.