I put my mouse in the microwave !!
Seriously. I have a bluetooth mouse that wouldn't enter pairing mode. It was connecting to *something*... maybe a smart switch or whatever. This cheap mouse has no way to enter pairing mode if it's connected to something.
So anyway, a microwave oven is a faraday cage. I turned the mouse on, tossed it in, shut the door and waited. It entered pairing mode quickly, and boom, connected to my tablet.
A+++ life hack by yours truly. Just don't start the nuker or magic smoke will come out 