you can use goo-gone or you can go to your nearest Home Depot and pick up a can of "Lift Off" Adhesive remover. it's the same thing as goo-gone except in an aerosol can. I prefer Lift-off because it don't stink, and have used it in the past (so I know it won't harm the paint)
remove the 3M tape on the back of the emblems, using the adhesive remover also (make sure you wash it thoroughly afterwards). then go buy some new 3M tape at the auto parts store. stick it on there..and BAM! you've got fresh tape.
I did that with my "Altezza" emblem. I just put the tape across the back, and used an Exacto knife to cut the excessive tape around the edges. Just be patient when you are doing it.
Like me first post.... I prefer "Lift-Off". spray on, let sit for 60 seconds..and then rub it off.. you may need to spray some more on to finish up. use a good soap to to wash it off, or else the new tape won't stick very well.