Use a carpet cleaning machine to get the deep dirt that settles into the fibers of the carpet. (Clean cloth seats this way as well.) It sprays the carpet with a solution of water and cleaner and then sucks the dirt and grime into a reservoir. A machine like this pays for itself after just a few uses. You can also rent one from a rental center or use a spray-on cleaner and a scrub brush instead.

1. Wash your car with the right suds

Even though liquid dish soap is a great degreaser, it’s not the thing to use on your vehicle’s finish. Yes, it removes dirt, grease and old wax. But it also sucks important oils right out of the paint’s finish. Use it repeatedly and you shorten the life of your paint job.

Instead of dish soap, use a cleaner formulated for vehicles (available at any auto parts store). Once you’ve mixed the suds, go one step further-fill a second bucket with clean rinse water. Use it to rinse the wash mitt often. That’ll remove most of the road grit from the mitt to prevent scratches. When you’re finished, throw the mitt in the washing machine to get it completely clean.

2. Pluck the finish

A car hurtling down the road at 100 km/h becomes a dartboard for any crud in the air. Your vehicle’s clear coat deflects some of it but can hold the sharper grit. Washing removes the surface dirt, but clay-barring is the only way to pluck out the embedded stuff.

Buy a clay bar kit (one brand is Meguiar’s Smooth Surface Clay Kit), which includes a lubricating spray and several pieces of synthetic clay. Prepare the clay by tearing a piece into four sections. Flatten one section into a small pancake in the palm of your hand and rub it over the paint with a back-and-forth motion. Fold the clay against itself, knead it and reflatten until the clay turns gray. Then toss it and use a fresh piece until you remove the “darts” and get a glass-like finish.

3. Polish the finish

Many car owners confuse polishing with waxing. But they’re separate steps. Polishing removes small surface imperfections and scratches and buffs the finish to a shine. Waxing adds more gloss and protects the finish from the elements. Most DIY-ers skip polishing because they don’t want to invest the money for a polisher or the elbow grease for a hand polish. But polishing your vehicle’s finish is the key to getting the best gloss (pros would never skip it).

Apply a dollop of polish to the pad and wipe the pad across a 2 x 2-ft. area. Run the polisher at a slow speed to spread the compound over the entire area. Then boost the speed and let the polisher do the work for you.

4. Get a mirror finish with synthetic wax

Some people swear by carnauba wax. It produces a deep, warm shine. But we prefer the wet-gloss look of the newer synthetic polymer waxes (also known as paint sealant) such as Meguiar’s Ultimate Liquid Wax. It’s pricier than other synthetics, but it doesn’t leave a white film on plastic or trim-which is a real advantage. Plus, it’s really easy to apply.

Apply the wax to the foam applicator and rub it into the finish with a swirling motion. Then wipe off the haze with a microfiber towel. Swap in a clean towel as soon as the first one loads up.

5. Remove the Dust

Most DIY-ers start cleaning their car interior  by shampooing the carpet. That’s a mistake-you’ll just get it dirty again as you clean the upper surfaces. Instead, start at the top and work your way down. Vacuum the headliner, dash, console and door panels. Then clean all the glass, and dust the nooks and crannies. Sweep the dust out of the cracks with a detailing brush. Catch all that crud right away with your vacuum.

6. De-stink the interior

To neutralize tobacco smoke, buy an aerosol can of Dakota Non-Smoke (dakotaproducts.com). Holding the can 12 to 14 in. away from fabrics, lightly spray the headliner (don’t soak it), seats, door panels and carpet. Then turn the fan to high and switch the system to recirculate mode (“Max A/C” if you don’t have that option).

Find the intake opening by holding a tissue near the blower motor. Then spray the mist into the opening. Leave the windows closed for at least one hour. Your vehicle will smell like baby powder for a while, but that’ll go away.

7. Clean the leather

This may sound extreme, but if you’ve got leather upholstery, buy a leather-cleaning kit and keep it in the vehicle (one brand is Leather Master Leather Care Kit with Ink Lifter). Why bother? Well, if you clean the “oops” right away, you really increase your chances of a complete cleanup. If you wait, lipstick, ink and dye transfers from clothing (and plastic shopping bags) can set permanently in as little as 24 hours.

Pretreat the leather with a conditioner before you start the stain removal process. Wipe the ink lifter directly on the pretreated leather and rub it in. Let it sit for 30 seconds, and wipe it with a clean cloth. Then apply leather cleaner and the leather protection cream.

8. Slide seats forward and clean out the junk

You’ll be surprised by what you find behind car seats. We found a lost cell phone, enough pens and pencils to equip a small office, and enough change for several vending machine lunches. Vacuum the seats, remove the mats and vacuum the carpet. Use a brush attachment for the dash and door panels. Don’t forget to clean out and vacuum those handy door pockets (another source of buried treasure).