Originally Posted by Moose
The car can pick up "rail dust", as well as contaminants in transit from factory to dealership.
Also, if the car has sat outside, exposed to the elements for any length of time, there will be surface contaminants.
Its not a necessary step, but it does make a difference.
As for any "wear", if done properly, this isn't an issue.
why did you have to bring up rail dust? Mines been sitting in rail yard for 10 days with no sign of leaving.