Try to peel it off first, and what's left I suggest soaking it in a solution like water & alcohol, and to get the glue off try scrubbing with a soft steel wool pad (such as those to clean algae infested fish tanks).
If the tape glue is really stuck (or you have an expensive mirror you don't want ANYTHING to happen to) there is a product called Goo-Gone which I LOVE. It gets stuff like tape, crayon (if you have kids or were acting like a kid) and all that other stuff off of pretty much anything. It's kinda oily and you have to make sure all the residue is off of your mirror to prevent streaks - but it's really worth it. It gets bumper stickers off windows in trucks and it works perfectly. See related link for more on this product
peel it off with your finger nail...its that easy
Warm the tape with a hair dryer or heat gun.When the adhesive is warm it comes off easier.
oil
Nail varnish remover, turpentine or lighter fluid are all very good at removing this but make sure you open windows/ doors ect when cleaning with these.
Remove the decorative cover to your 1997 VW tape player. Remove the tape player retaining screws. Remove the wiring harness from the back of the tape player.
Remove the tape player decorative cover. Remove the tape player retaining screws. Remove the wiring harness from the back of the tape player. Reverse the process to install the new tape player.
Soak the paper with spirit ( ethyl alcohol) and then remove the sticky tape.
Remove duct tape adhesive with Goo-Gone or Goof-Off.
Duct tape won't remove plantar warts.
remove the radio.and once outside remove the tape deck wich is screw to te radio.
How do I remove cassette tape stuck in my 1998 Volkswagon beetle
If the duct tape is just taped on the floor, just carefully remove the tape. Using the edge of a knife helps lift it off the floor to start with.
Most of the time you will need to break the tape.