Detailing Part 3: Interior Cleaning and Protecting
Keeping a vehicle's interior clean and protected is just as important as the exterior. Over time the sun, heat, cold, and the wear caused by entering and exiting the vehicle can take a toll on the interior surfaces if they're not properly cared for. Interior cleaning and protecting steps aren't as critical in terms of what order you do them in as the exterior, but I've found a routine that works pretty well, and saves time. You may have to experiment and find what method works for you, but here's how I do it.
Start with good products, just as you would on the exterior. As with the exterior, I mostly use Griot's Garage products on the interior. They're well designed, don't contain dyes or perfumes that can harm leather or other surfaces, they work well, and a little goes a long way. I specifically use their Ultimate Interior Kit, which includes Glass Cleaner, Interior Cleaner, Leather Care Spray, and Vinyl and Rubber Dressing with foam applicator, as well as glass microfiber towels and interior microfiber towels. Buying these items as a kit saves around $16.00 as apposed to buying them seperately. One thing to note, the Glass Cleaner contains alcohol. This produces streak and smudge free glass when used with the glass microfiber towels, but because it contains alcohol IT'S NOT TINT SAFE. My windows are tinted, so I use the Glass Cleaner only on the windshield and exterior glass surfaces. For the tinted windows I've had so/so luck with Armor All Glass Cleaner, but I've heard good things about Invisible Glass and plan to try that next on my tinted glass surfaces. Hopefully Griot's will develop a glass cleaner that is window tint safe in the near future.
For this maintenance you'll need:
Interior Cleaner
Glass Cleaner (if windows are tinted be sure it's tint safe)
2 Glass Microfiber Towels (yes they're different than regular microfiber towels)
2 Standard Microfiber Towels
Dash and Vinyl Surface Dressing (watch out for the greasy ones get one that's petroleum distillate free)
Swiffer Duster
Shop Vac
Difficulty Rating: 
I start by cleaning the exterior glass surfaces. The best method I've found is to spray some glass cleaner on your microfiber towel, then wipe down the window. Spraying cleaner directly on the window makes a mess on the paint and wastes product. Cleaning the exterior glass first will make it easier to tell what areas are dirty on the inside since you'll know the outside is already clean.
Next, I use the Swiffer to dust the interior surfaces such as the dash, radio, instruments, console, etc. This will remove the majority if the dusty keeping the microfiber towels cleaner. Once dusted, I spray some interior cleaner on my a microfiber towel and wipe down all the interior surfaces including the leather seats. I've tested Griot's Interior Cleaner on the Challenger's leather and it is perfectly safe. If you use a different brand be sure to test a small area before use to make sure it doesn't lift any of the color from the leather.
Once the interior is wiped down, now it's time to protect it from UV rays. I start by spraying some Vinyl and Rubber Dressing on the blue foam applicator. Starting in the rear of the car I treat all the plastic and vinyl surfaces by wiping them down. This product is not at all greasy and leaves a nice satin finish. If you get spots that aren't full absorbed by the surface, just wipe it down with a microfiber towel and you're good to go. A little goes a long way so use sparingly. Out of all the interior products from Griot's this one is my favorite. I hate that greasy stuff the other guys make. Don't forget the back of the front seats when performing this step.
Next, I clean the interior glass surfaces. The reason I do it at this point is so that I can wipe off any of the Vinyl and Rubber Dressing I might have gotten on the glass. Spray some glass cleaner on a glass specific microfiber towel and wipe them down. Again be aware that not all glass cleaners are window tint safe, so purchase your cleaner accordingly.
Next, I treat the leather with some Leather Care Spray. I spray this directly on the leather surface and use a microfiber towel to buff it in. This is also a non-greasy product and simply keeps the leather conditioned. I treat the back first, then the front.
Finally, I remove the floor mats and vacuum them as well as the interior carpet areas. If you don't have a good shop vac, I recommend you get one. They work much better than the vacuum you'd use for your home. If you keep an eye out, you can pick up a really nice one at Home Depot on one of those Black Friday sales, the day after Thanksgiving. The unit I have is normally well over $100 and I got it for around $50 on a Black Friday sale at Home Depot. This unit has a powerful motor, can be used as a blower, and I was able to pick up a muffler for it as an accessory that cut the noise by 50%.
That's it. Now you should have a perfectly clean and protected vehicle.