Using water to see if frying oil is hot enough can be dangerous. Instead, dip the handle of a wooden spoon in a deep fryer or skillet to see if the oil bubbles, says pro chef Maricel Gentile.

They’re inexpensive and easy to use, and they help keep you safe when doing DIY electrical work. Solution: Test. Use. Verify. First, test the tester by holding it to a known live circuit, like a ...