Float or Sink
One way to test if someone accused was a witch was the “swimming test”. Funny name since the person being tested could not swim due to being tied up. A finger tied to the opposite toe would begin and then that person was lowered into a body of water.
If they floated, they were deemed a witch. If that person sunk, they were innocent. Granted, if they sunk, those watching had to pull them out in time before they drowned.