the black stuff is a form of tint that is used on many cars front & rear. its actually along the edges of front & rear windows too. its actually ceramic and WILL NOT COME OFF.
when you tint a rear window, or that strip in the front, and the black stuff/dots are on there- you actually gotta sand it down with a fine sand-paper to level it enough for the tint to have glass to stick too.
trust me when i tell you- those black dots are not going anywhere with ezpass velcro stick-ons!