Unlike dirt, oil and grease do not wipe off surfaces with just water and a cloth. When these substances get on your car door, you can't use just any cleaner to remove them. You must be very careful, and use the right kind of cleaner and method to remove oil and grease safely from the paint. Some products may dull or scratch the finish. Always use a paint-safe product. These are readily available at hardware and automotive shops.
Spray an automotive degreasing cleaner on the oil and grease spots. Give the cleaner time to start dissolving the grime. It will usually take from 5 to 15 minutes. You can also use automotive cleaners that are concentrated and must be mixed with water and applied with a sponge. For small oil and grease spots, however, the sprays are more convenient to use.
Put on rubber gloves. Fill a bucket with hot water and saturate a soft sponge. Your sponge should be very clean--free of any abrasive grit--so you don't scratch your car.
Gently scrub the grease and oil spots. Use plenty of water, and spray more cleaner if the grease spots are stubborn.
Douse a microfiber cloth in water. Use this sodden cloth to rinse the car door. This is to remove excess cleaner.
Use a clean, dry microfiber cloth to rub the door dry. Drying is important to avoid water spots.
Some car shampoos will also remove grease and oil. If the whole car is otherwise dirty, you may try washing the whole car with a strong shampoo. If grease and oil spots remain, then spot-treat them.
If the grease or oil has been on the door for several days, there may be some haze or discolouration on the door. In this case, you'll need to polish the area with car polish after cleaning. Dish detergent may dull a car's paint job. Avoid using it on a car's exterior to remove grease.