Vacuum
To begin a serious clean up, you have to take the seats out. Removing front seats can be a bit tricky. This also allows you to clean the seats without being hunched over in a small space. Once the seats are out, you may discover all kinds of treasures. If you find any screws or washers, save them. They probably go to something on the car. You may also find missing knobs and broken pieces that you can reattach or glue back together. Pick up all the big stuff and then get out the shop vac or household vacuum and begin vacuuming. Make sure to get in all the cracks and crevices. Once you can see the bottom of the car and all the dust has been sucked up, you can start peeling away the grime.
Soap and Water
Depending on what material your seats are made of, mild soap and water will remove much of the surface dirt. Use a sponge or a soft rag. White is the best color for rags. Colored rags can leave streaks of dye behind. The more you clean, the more dirt you will find. Use a soft toothbrush for tight areas and air vents. You can also use cotton swabs for crevices and seams where dirt seems to accumulate. If you find any sticky areas or spots with scuff marks, try a little baking soda and water before you reach for a harsh cleaning product. Baking soda can work miracles on some substances and it won’t fade or hurt the surface. For stubborn stains on surfaces other than wood or leather, Murphy’s Oil soap works pretty well. You can buy it almost anywhere and it can be used for cleaning almost anything. Blue Coral also makes some great car cleaning products, but you’ll pay a few cents more. If you can remove the part on your car that you are cleaning, this will help. Just be sure not to snap off any holders or plugs. Interior trim parts usually unscrew or slide out of a track. Never force a part. If you can’t remove something, just leave it on the car and spray it down with your cleaner, then wipe it down and you should notice a slight shine.
Dash Parts
If you have an older car, your dash is probably black and if it has sat in the sun for the last 10 or more years, there are probably some cracks. Unless you plan on showing your car, my advice is to live with the cracks. There are repair kits out there which claim to “sew up” dash cracks, but I wouldn’t waste the money. The crack will still be noticeable. Sometimes repairing a crack will cause another one to start somewhere else. You can keep your dash from cracking further by applying a UV protectorate to the dash and other black parts. There are a lot of products on the market. Look for ones that are water based rather than silicone based. Be careful when applying these products to steering wheels, floor pedals and shift handles. These products will make surfaces very slippery.
Carpeting
When cleaning carpeting, pre-treat any spots with an automotive stain remover. Spray on an automotive carpet shampoo, or a multi-purpose cleaner that state they are safe for carpeting. Scrub and then let dry. To speed the drying process, leave your doors open, but make sure you shut off the interior lights by sticking something in the door jamb that keeps the buttons closed. Dome and dash lights will drain your battery and they can get very hot. Once you’ve cleaned your vehicle’s carpeting and upholstery, consider protecting it with a spray fabric protector that will help repel future dirt and stains.
Leather
If you own a car with leather seats, you will need to buy some kind of leather conditioner and cleaner. A lot of the leathers used on domestic vehicles are treated with a thin plastic which is used to protect them. You can treat these leathers with the same products you would use on vinyl upholstery. European cars often feature uncoated leather upholstery. You should use a specialized leather product on these leathers.
To find out the kind of leather you have, put a drop of water on an inconspicuous part of the upholstery. Uncoated leather will absorb the water, while coated leather will not. Before you use any leather cleaner or conditioner, test it for color fastness or marking on an inconspicuous spot. Use a leather cleaner first by rubbing a generous amount into the upholstery. To get rid of those dirt wrinkles, you may have to use a stiff nylon nail brush. Make sure there is no cleaner residue left. Then apply the leather conditioner to restore the oils, life and sheen.
Glass
Glass is hard to clean. There always seems to be streaks and fingerprints no matter what product you use. Household glass cleaners are fine, but don’t always work well in the automotive world where bug splats and water spots are constantly assaulting your car. The same goes for the newspaper and vinegar-water solution method. You may end up getting more streaks because some newspapers are now using water-based inks which will release when wet. Automotive glass cleaners are designed to prevent streaking. Use lint-free paper towels or clean cotton towels. When cleaning side windows, clean the top edges and next to the rubber gaskets first. These are the dirtiest parts of the window and should be cleaned with a separate cloth before you tackle the main part of the glass. Always spray the glass cleaner on your cloth and not on the glass itself to avoid overspray on the vehicle’s painted surfaces.
Summary
Don’t be in a hurry to clean a really dirty car. You will have many buckets of black water before you finally begin to notice a difference. Depending on the age of your car, you could be removing 20 or more years of dirt. This isn’t going to happen over night. Once your car is clean, try to keep it that way. You can sell a clean car for much more than a dirty car. If you eat in your car, carry napkins and handi-wipes. If a can of soda is spilled all over the floor, clean it up as soon as possible. Once stains set into carpets and upholstery, they’re hard to get the out.