This is not going to be done in a couple of hours, so you'll need a place to keep these parts so the paint can cure properly (overnight is best). Make a list of the different materials you're going to be painting before you go get supplies. Krylon has developed a new paint called Fusion, designed specifically for plastics, although I have not used it (it was kind of pricey). This paint is meant to be applied directly to plastic, eliminating the prep time (sanding and priming), but again, I have not used it and cannot verify its claims. More information can be found about this paint at http://www.krylon.com. Vinyl will need a paint that can penetrate, allowing it to be absorbed... local part houses usually carry vinyl paints in various colors. If you plan on actually coloring the carpet, there are carpet paints available as well, but I have not tried these either, so can't say whether or not they actually work and won't rub out. When removing panels from the car's interior, it is always a good idea to put the screws and/or other fastening devices for individual panels into seperate baggies, marking them and leaving them beside the location of the panel when it's in the car. To properly paint the "slick" plastic pieces, you will need to lightly scuff them with the fine grit sand paper. Almost every color looks "cloudy" when it has been sufficiently sanded. Before painting, you should lay down newspaper or cardboard to preserve the work area where you'll be painting. It is also a good idea to use small pieces of wood or cardboard to shim the work up off the work area so it can be more easily painted and handled.
Cleaning
This step should NOT be skipped by any means. Using one of the soft cloths, scrub down the panels with the soapy water. This cleans dirt, grime, protectants (like Armor All), and oils from the painting surfaces. Be sure to get any and every place that paint will be applied. This is a good time to go ahead and clean the entire panel since its already out of the car, so go ahead and clean the back sides as well. After the panel has been washed with the soapy water, rinse or wipe it down again with plain water and a clean cloth. I would not recommend rinsing pieces that have any kind of non-removable hardware or other materials that would hold water, these should be wiped off. When a panel is clean, dry it with another lint-free cloth and let it sit so any remaining dampness can evaporate. Some panels have trim pieces, louvered vents, or other hardware that may or may not be removable. If it is, take the hardware off and clean it seperately, making sure to get the places on the panel that you couldn't while it was in place. Electronics should be removed prior to wetting the panel to avoid potential problems in the future. If you're painting the dash as well, it's fairly easy to remove, but there are a lot of pieces to come off after it's out, and can't be rinsed, only wiped off. Any areas or pieces that are to remain unpainted should be covered with masking tape AFTER the panel has dried from being cleaned. You can tape paper down around all of its edges for masking large areas instead of using a lot of tape.
Painting (finally... : þ)
** If you're using a primer, follow the directions for using regular paint (below). If I had primed the pieces prior to painting, I would have had 2 coats of primer to ensure even coating (including the "mist" coat). **
When painting, the can should be shaken every 10-15 seconds of use to keep the ingredients mixed well. This allows the paint to flow better and cover the work easier. While spraying, move the can from side to side, using short, quick bursts. Don't stay in one place or it will run. If you are painting flexible vinyl, like a door panel, it is not recommended that you apply a clearcoat. The vinyl paint is made to be flexible, yet durable. It should be available in gloss as well as flat.
For the first coat of paint, you'll need to "mist" the panel unless it has been primed. What I mean by "mist" is just enough paint to give the panel a grainy texture without it starting to look wet. The easiest way to do this is to hold the can a little farther back than what is indicated by the directions, use long bursts of paint, and move the can quickly from side to side, changing the target area often. This coat should be allowed to dry according to the paint can directions (usually about 20 minutes between coats), and may or may not completely cover the panel. If it does not, and is splotchy in appearance, don't worry - that's why there are at least two coats. The second coat should be sprayed on thicker, giving the panel a "wet" look, but understand that as soon as the paint begins to look wet, this is enough and any more will cause it to sag or run. Stay patient. Allow this coat to dry as well. If you desire more coats, or if the paint is heavier in some places, continue in the same manner until you have enough coats to give it a uniform appearance, allowing it to dry between coats. Avoid doing "touch ups" in one particular spot, as this causes a darker area where there is more paint. Instead, if touch ups are required, put on another coat that is heavy enough to fix the flaw.
To apply the clearcoat, the paint must have dried for the minimum allowed complete-dry time on the can (usually about 4 hours). Clear enamels don't get along with other paints AT ALL if the paint has not fully dried (they will react, "cracking" the underlying paint as the chemicals from the clearcoat do their job and try to penetrate for better adhesion). If the freshly painted piece gets a little dust on it during its drying period, use a soft, lint-free cloth to lightly dust it off. DO NOT APPLY PRESSURE. The clearcoat is sprayed on in the same manner as the paint, with the exception of misting the panel. When spraying clearcoat, go directly to the second stage of the painting process. There is no need to apply the mist coat here because the clearcoat will adhere to the other paint just fine. Add as many clearcoats as you want, I use a good 3 or 4 coats for better protection and a glossier look.
After you're completely done painting a panel, you can usually get under it with your hands or a ruler to lift it so it can be moved. Set each panel in a clean, dry place where air can circulate freely. Allow the panels to cure overnight for best results and durability of the new paint.