I bought my Pearl White 2012 Mazda5 Sport AT in October. After the first couple months, as I periodically visited the car wash, I noticed little areas of tiny rust spots on the paint, mostly on the lower half of the doors. With a little rubbing they would go away but when I looked this up, I found out about "rail dust". These small metal particles attach themselves to the clear coat and eventually rust. It's not harmful unless left on indefinitely. Being my car is white they showed up readily. Anyway, being winter in Vermont, it was impossible to keep the car clean enough to remove the rail dust. Until today! I got some IronX product from AutoGeek.com and then used the clay bar with some Meguiar's Quick Detailing spray. The IronX seemed to work well, loosening a lot of the metal and the clay bar easily took away the rest. I've never clay-barred a car before and I've never been more impressed with the performance of a detailing product. I recommend this to everyone on this forum.