Taken from zoltiz. BTW there has been at least 1 post about this...
Debadging the "tC":
1. Select a nice hot day, park in the sun, let the area around the emblem get as
warm as possible (or use a hairdryer)
2. Pry the emblem off with your fingers (try to leave as much adhesive on the
emblem as possible).
2.1 If simple "prying" does not work - use floss to "saw" through the adhesive.
3. Clean up the mess: try to remove as much lefover adhesive as possible with
your fingers, the rest comes off with any adhesive remover. I like the DucTape
brand adhesive remover - it smells like oranges