This is a test of commonsense. Complete the next sentence:

How to shampoo car interior
Clear out any debris.
Any wrappers, papers, stones, or other noticeable pieces of junk that have cluttered up your car interior until now must be cleared away before you can begin shampooing.
Vacuum the car interior.
Vacuuming removes the majority of large dirt particles, making the process of shampooing both easier and more effective. Shampooing should be used primarily to get rid of greasy, smelly gunk that ordinary vacuuming or sweeping cannot remove.