i got a pontiac badge and bonneville badge... i had a hell of a time getting them off wihtout breaking them. so i clena the backs off and now what should i use to make a strong adhesion to the car now?

3M double sided foam tape has worked well for me in the past. Just make sure that the surface you stick it to is clean and they'll be on there as good as they were.

Last time I needed to do this, I found a tube of 3M (I think) "Emblem and Weatherstrip Adhesive," which was basically a clear silicone glue or sealer. Worked fine, but then I think most any similar flexible adhesive will work.

The main point is that you don't want something that dries solid and inflexible, like epoxy, because body flex and thermal expansion in sunlight will crack it loose pretty quick.

You should be able to find the right stuff at NAPA or AutoZone...

ok either my curent badges are warping or the adhesive is coming undone.

whats the best way (not with a key) to remove the the crud from my car? goo gone?

I used professional label and sticker remover made by Dominion sure seal ltd.
squirt squirt wipe and it was gone. $5 at canadian tire.

Goo Gone works great. Make sure you clean it all off when you're done.

Also Bug & Tar Remover might work for you.

Even if you're starting with a clean surface, you might want to clean it with Bug & Tar Remover first in order to remove car wax layers and ensure a proper adhesive bond. I had to re-glue a lot of stick-on bodyside moldings before I learned this.

Yes, you have to wax around it again when you're done.