From the Dashboard to the Window controls, Plastics are widely used in most modern cars today. They're cheap, lightweight, and incredibly durable. Here is a step-by-step process for cleaning them quickly, and safely,

Here are the items you'll need.

- Steam Machine
- Interior Brush
- Microfiber Towel
- Water
- Plastic Cleaner

Steps
1. Spray the cleaner directly onto the plastic in a small area. Immediately wipe the plastic with a dry microfiber towel in light to medium pressure. The fibres within the microfiber towel are designed to pick up and hold the oils and dirt left behind on the plastic.
2. Respray your interior cleaner and then use a soft bristle interior brush to agitate the embedded grime. A lather will be created that holds the suspended dirt.
3. Wipe the foam quickly with a microfiber towel before it dries, otherwise the grime will simply be redistributed and not removed.
4. If the stain persists, the next and most aggressive method is to use an interior scrub pad with light to medium pressure. Once again, apply the cleaner first, and very gently scrub the leather. Extreme caution must be taken with this technique to avoid rubbing away the pigment or colour. The age, condition, and the specific type of leather will dictate its strength
and vulnerability using the scrub pad technique.
5. If you have access to a steam machine, they can be very helpful if used properly. To do this, wrap the head of the nozzle in a microfiber towel. With the nozzle pressure on medium, scrub the plastic to kill bacteria, germs, and allergens. This is a great option, especially on new car acquisitions, pet owners, and families with young children.
6. You can also end the cleaning with a Dashboard Spray Polish from Autofactor.
Most of the time spent with your car is, well, spent inside. So a quick leather cleaning, or light wipe-down during each car wash, will help avoid the constant build-up of body oils and grime, keeping your car looking fresh and new.

Source - http://autofactorng..com.ng/2016/07/how-to-clean-car-interior-plastic.html