Because most tops on convertible cars are made of vinyl, over time they can begin to fade and look dingy, particularly if they are a lighter colour such as tan or beige. You can always replace your top with a new one, but that might be a waste of money and time if the top is fundamentally sound and not torn. Instead, you can dye the top and, in the process, restore it to a like-new condition. You can also easily change the colour of a lighter top to a darker colour that will hide dirt and discolouration.
Buy the vinyl convertible top dye. Forever Black offers a very good convertible top dye called Black-Top, which will dye your top a black colour (See Resources 1). There are also companies such as PDH that make dyes in a variety of colours. (See Resources 2)
Clean the top thoroughly with mild soap and water. You can use a cleaner such as Simple Green or even dish washing liquid. Use a detailing mitt and plenty of water. Finish the cleaning job with a soft bristle brush, scrubbing the top until it is completely free of dirt. Let the top dry overnight or in the sun for an afternoon before applying any dye.
Mask off the paint, windows and anything else near the top to avoid getting any dye on them. Also, make sure you wear old clothes and rubber gloves to avoid getting dye on your skin.
Apply the top dye according to the directions on the package. Using a new, soft paintbrush, start in the middle of the top and move outward. Apply the dye in one direction and ensure that there is even coverage.
Apply between two to three coats of dye to get consistent coverage. Let the top dry for at least 24 hours. Apply a weatherproofing product such as Scotchgard Auto Protector.