1) Preliminary Cleaning
Remove and clear out any debris, wrappers, papers, stones, leafs, or other noticeable pieces of junk that have accumulated in your car interior until now, before you start the process of shampooing.
2) Completely 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 spots, smelly gunk that ordinary vacuuming or sweeping cannot be removed.
3) Shampooing the Carpet and Upholstery / Fabric
Always select the right materials perform your research for better results; a general spray-on carpet shampoo will work well enough for the carpet in your car. You should also use a brush, like a stiff tire brush made with soft plastic special for this type of job
4) Work on small areas at a time
To avoid having to soak and re-soak the car's carpet a couple of times, focus your attention on one small area of the car before moving onto the next one, rather than shampooing the entire car at once. Oftentimes, people find it easiest to start with the driver's side floor before moving across the front of the car to the passenger's side, then circling around to the back
5) Remove all of the floor mats
These mats must be removing and clean separately from the rest of the car's carpet
6) Pre-treat heavy stains on the carpet
Problematic areas with signs of stains like tar or oil may not be removed sufficiently by simple carpet shampoo. Use a cleaning product specifically geared toward treating these heavy stains to pre-treat the carpet before shampooing it. Always read and follow the directions on the cleaner's label. Usually, you will need to spray the stain directly onto the stain, covering it completely. Allow it to soak for several minutes before washing.
7) Shampooing the Upholstery / Fabric
Mix special upholstery shampoo into a bucket of water. You can use the same shampoo you used for the carpet, but one that is specifically designed for use with upholstery makes a better result. Use plenty of shampoo and mix very well to create a great deal of foam.
The shampoo foam itself is what you will use to clean the upholstery instead of the soapy water. Upholstery, especially when made of seat cloth or velour, has a tendency to look dry even after being soaked. As such, it is very easy to over-apply cleaner if using soapy water or a spray-on shampoo.
8) Scoop some of the foam up
With your brush and work it in. Lift the foam onto the bristles of your stiff bristle brush, getting as much foam as possible and as little actual water as possible. Transfer the foam onto the upholstery and firmly scrub it into the fabric using the brush. Use as little as possible to cover the upholstery
The foam in your bucket will likely die down as you work, so you may need to re-agitate the soapy shampoo water periodically to create more foam. If necessary, you may even mix in additional shampoo
9) Remove extra water
With a dry terry-cloth towel Press the towel into the upholstery firmly, moving it along in straight, single-direction lines to wring excess water out of the seats and into the towel.
10) Allow the remainder to air dry
Most of the moisture will need to dry out naturally. Prevent mold or mildew from forming by leaving the windows rolled down or the car doors open, improving air circulation. You can even use an electric fan to speed the process along.