When your vacuum cleaner is on our workbench to be cleaned and serviced, a vacuum cleaner repairman with many years experience is on the job. He must disassemble a machine with many small parts, and take caution to not break anything. All screws and fasteners must be kept organized and labeled, because it has to go back together exactly the same way it came apart. As he removes each small part, he carefully cleans it with the proper cleanser. The key to a proper functioning vacuum is cleanliness. Some of the small parts are often plastic and easily broken, so great caution is taken. When he is done with this step of the job, he has a fully disassembled vacuum cleaner, in many pieces!
As you can see in the pictures, there are many crevices and holes where dirt builds up.