2. Once a year or every 20,000 km (12,000 miles) mileage, it is advisable to steam clean the interior surfaces of the body. After removing all traces of dirt, oil and grease, the surfaces can be inspected for signs of corrosion, damage to brake lines, wear of electrical wiring insulation, damage to drive cables and other faults. Upon completion of this work, it is necessary to lubricate the front suspension components.
3. At the same time, steam clean or wash the outer surfaces of the engine and engine compartment with a degreasing agent.
4. Particular attention should be paid to the wheel arches, as the protective coating may separate from the inner surfaces and small stones and grains of sand flying out of the wheel protectors will cause damage to the paint and, as a consequence, the development of corrosion of the panels. If traces of corrosion (rust) are found, they should be removed to bare metal and the surface covered with anti-corrosion paint
5. The car body should be washed approximately once a week. Thoroughly wet the car body surfaces to soften the dirt, which can then be washed off with a soft sponge or a stream of water. Careless removal of stuck dirt can damage the outer layer of paint.
6. Tar or asphalt stains that fall on the body from a hot road surface can and should be removed using a rag soaked in solvent.
7. Rub the body and chrome trim elements with wax once every six months. Remember that when using cleaners to clean chrome surfaces, some of the chrome will also be removed along with traces of corrosion - try not to use such solutions too generously.
(The article text was copied from an online resource BMWman.ru)