In recent years aluminum has replaced steel in the manufacture of cars. This is because aluminum is lighter and stronger than steel, and is less likely to rust or corrode. It's also cheaper than steel, and has good thermal properties [source: Kinetic Casting]. Every engine cylinder has an aluminum valve cover. There is a rubber gasket between the valve cover and the engine block, which prevents the lubricant oil from leaking out. Some oil does leak, though, and that causes the valve cover to get that "blob effect." Read on and find out how to polish your car's aluminum valve covers.

  1. Shut the car engine.
  2. Detach the valve cover and put it on the ground. If you can reach the valve cover easily, then there's no need to remove it.
  3. Hose down all the dirt from the cover. If the cover remains in the engine, rub it with a wet rag.
  4. Scrub all the grime off, using steel wool. If steel wool doesn't work well enough, you can use a steel brush.
  5. Apply a degreaser to the top of the cover. Let it do its job for 30 minutes.
  6. Scrub the cover thoroughly again with steel wool.
  7. Rinse off all the degreaser. If the cover's not completely clean, repeat the procedure [source: Mobil Oil].
  8. Dry off the cover with a dry cloth.