That show room appearance of your new vehicle can be maintained to some extent by using the proper wash methods. Each vehicle comes with protective wax. Keeping that intact as long as possible protects your purchase.
Do clean off the crud such as bird droppings, dead bugs, and atmospheric chemicals leach acids that can cause wax to slowly disappear. It’s important to use the correct wash agent which is milder and not abrasive.
Don’t use glass cleaner on the paint, dishwashing detergent or hand soap. Use a natural, soft sponge or a lamb’s-wool mitt to apply the suds. Different areas of your vehicle call for different cleaning methods. Road-tar deposits, rubber, and grease often congregate around the lower edge of the body and wheel wells. For those areas, a stronger product may be required such as bur-and-tar remover. Use a non-abrasive cloth to remove material.
To clean the tires and wheels use a separate sponge. Otherwise, brake dust, sand and other material could be transferred to the vehicle’s finish that’ll eventually become marred.
Additional tips can be found at: http://www.consumerreports.org/cro/news/2012/12/do-s-and-don-ts-of-washing-your-car/index.htm