How to remove rail dust on coated car.

[Temple90]

Hey everyone,
I have a white Sti that I had ceramic coated last year.
With the nicer weather I gave it a wash today and noticed that some rail dust is present especially on the trunk
and rear bumper.
prior to coating the car I was using ironx followed by a good sealant in the spots i hit.
Will using ironx on a coated car remove the coating? Any tips for removing these deposits?

thanks!

 

[The Guz]

Depending on the manufacturer of the coating it is often recommended to do a chemical decontamination at once a year.

What coating?

 

[Temple90]

Sorry for the late reply could not find this thread again! I had the car coated with opti coat.