I don't have the invisible shield but I did buy a couple of film shields (my Nano is fine but a couple of scratches on the missus').

Don't need to wet it. Works all right. Screen is still useable. I use firm on my Nokia 6630 screen to keep fingerprints off and don't even notice it anymore and this film is the same type.

Also, it comes off and with a quick rub with a Radtech or Oakley cloth and no traces left whatsoever.