Problem scenario
You affixed some 3M tape to a wall. You want to remove it without damaging the surface it is attached to. What do you do?
Solution
With 3M tape (double sided tape to hold or affix a sensor), remember to pull it straight down parallel to the wall (rather than pulling it away from the wall). If this tape stretches enough, you will be able to remove the sensor. You do not want the tape to pull off the paint or wallpaper (by pulling it away from the wall or using some chemical cleaner like Goo Gone). The landlord could charge you for the paint removal and/or drywall removal. Here is a video that illustrates the two types of removal:
If you do not have access to a piece/edge of the 3M tape to pull parallel to the wall to stretch it and remove it the way it was intended, (e.g., the object adhering to the tape is blocking you from an edge) use dental floss or a hair dryer.
The hook or object may pull suddenly. But it is better to have a small amount of pain from the sudden plastic object hitting your hand than pulling up paint from the wall.