What I have worried about was sealing "in" the contaminates or anything I haven't removed before applying a new layer of
SG. Now I just like to keep my car in the garage for a few days and apply 4-5 layers or so of SG, and just use OGSO in-between washes. Then I will start all over again… maybe about 6 months later with the ABC system.
With my Steel Blue car, I keep layering on the Z-2 though. The specks are a lot less noticeable on medium metallic colors… and since I “Z-1” about every 4 or so layers, the cleaners in Z-1 usually take the majority of specks off.
~bw