This question has options. How would someone go about accomplishing this goal?
To remove expired registration stickers from your car easily,

OPT:
 - apply methyl alcohol to the sticker.  Wait a few minutes and then use a razor blade to help peel it off.
 - apply rubbing alcohol to the sticker.  Wait a few minutes and then use a razor blade to help peel it off.
apply rubbing alcohol to the sticker.  Wait a few minutes and then use a razor blade to help peel it off.