About.com suggest these steps to take when you clean your grill.

  1. Remove cooking grates and set them in warm soapy water to soak.
  2. Fill a small bucket or pan with warm soapy water.
  3. If it's a charcoal grill then remove the coal grate and brush out the insides.
  4. If it's a gas grill, remove briquettes, lava rocks or metal flame shield to expose burner.
  5. Clean out ash and residue from around burner, careful to make sure the burner is in place when you are done.
  6. Use a stiff wire brush and a little soapy water to gently scrub the inside surfaces of the grill.
  7. Remove any particles from grill and reassemble.
  8. If gas, brush off briquettes or lava rocks or wash metal flame shield in warm soapy water.
  9. Remove cooking grates from water and brush clean with the wire brush.
  10. Coat inside surfaces and cooking grates with cooking oil or spray.
  11. Put grates back on grill
  12. Allow the whole grill to air dry.
  13. Allow an extra five minutes of heating time the next time you grill to make sure any cleaning residue has burner off.