If your vehicle gets driven in the rain, it will gather traffic film!
Traffic film is a term for the accumulation of the oil, gas, brake fluid and other motor vehicle fluids that get leaked onto roadways. When driving on a highway, notice the darker line of asphalt in the middle of the lanes. That is where these fluids have stained the road. When roads become wet, these fluids get splashed onto your vehicle.
In order to remove any topical traffic film, a pre-wash/pre-soak can help breakdown the oils. Follow up with a normal contact wash and you should be fine. However; over time, typically from infrequent washing and maintenance, this film can actually migrate into the pores of the paint and a light polish with a cleaner wax or all-in-one product will be needed.
These cleaner waxes will have cleaning solvents to remove any bonded traffic film or “dirt staining”. You will actually able to see your applicator pad getting dirty as a result if film is being removed. This process can easily be done by hand or with an orbital machine.
The best way to prevent a buildup of traffic film is proper frequent washing and protection! Whether you like waxes, sealants, or coatings they all need to be cleaned and maintained on a regular basis.