Im with bob on this one. Ive been using these on my grills, dash board vents etc, panel lines, For quite sometime. I think i got every Size there is plus the colors. And he is right, Sometimes its the Chrome itself, Heres what i do, if it wont right in the recess of a grille cause of the film, Take a toothpick, and hit the recess back and forth a few times and its scuffed up enuff to use the pens Well happy modeling