how to attach coroplast?

[bzipitidoo]

Now that I've acquired a few coroplast signs from the primaries that have just ended, I'm wondering what's the best way to attach them to the car.

I'd like to do a grill block on my Metro. Specifically, I'm thinking of being conservative and blocking only those parts which don't have any coils behind. The lower part of the bumper has two horizontal slots that extend nearly the width of the car. These slots are divided into 4 parts by a connective part in the center, and two more just inside the headlights. I'm thinking of blocking the outer 2 parts.

So how to do it? Nylon ties through holes in the coroplast? Sheetmetal extended through the openings to provide a mounting surface and to hold screws? Tape? Glue? For that matter, can the coroplast take the beating it will get at the front, with bugs, dust, gravel and so forth smashing into it?