My wife just bought a new white 2013 Hyundai Elantra. Before I applied the 1st coat of wax I noticed some grey dots on the doors about the size of a tip of a pen. I am not sure if this is rail dust since they are grey not brown but I tried to remove with my finger nail and also varsol but would not come off. I am thinking it may be under the clearcoat from factory. I am going to try some solvent and a clay bar but wondering if anyone else had seen this and how they removed them. Also I have been using Mother's Canuba wax and cleaner but someone at a detailing shop said I need to use the 3rd step wax sealer. Is this sealer necessary to protect my paint?

Avoid unnecessary friction on the paint. If it is in the clear coat there is no easy fix. If it is on the paint a paint deoxidizer such as ALR*C could offer a quick and easy fix.

Yes its under the clear coat unfortuantly. I have just decided to live with it rather than have the doors repainted and possibly not match.