The plastic face of a car speedometer tends to get dirty as the car ages. As a result, it becomes harder to see what your current speed is, making you more likely to be stopped by for speeding or possibly even get in an accident. You can clean the speedometer's face, though, so you are able to clearly see your speed.
Roll down the windows of the car. If the car windows are electric, turn on the car to roll them down, then turn off the car.
Spray the plastic faces of the speedometer with the ammonia cleaner. Wait 30 seconds before continuing.
Wipe the face down with a paper towel. Use a left-to-right or up-and-down movement wherever possible.
Clean the remaining sections of dirt with the cotton swab. Dip the swab in water or spray ammonia to help clean the areas.
Repeat the above steps if the speedometer is still dirty.
Close the windows when you are finished.
