begin with the use a heat gun/blow dryer....apply heat to the letters and then use a piece of fishing line to remove emblems. slide the fishing back and forth under the emblem to loosen adhesive...do NOT pry or pull on loose emblems. use an adhesive remover (3M, goo gone) to remove remaining adhesive. then polish with a non abrasive wax/polish.

as for reusing the emblems....you would have to probably replace them to have them re-adhere properly.