Household Mysteries Solved: Why Microwaves Have Black Dots on Their Windows and Pens Have Holes in Their Caps

Have you ever wondered why your microwave oven has all those black dots on the window? What about that hole in your pen cap? Inside Edition talked to lifestyle expert Trey Boge to learn all the answers.

First up—the black dots on the microwave. “It’s designed to prevent electromagnetic energy from escaping the microwave and protects you from radiation,” Boge said.

That little hole in the pen cap—it can actually save your life. "It’s a safety precaution in case a child or an adult swallows the pen, it allows air to go through so they don’t suffocate,” Boge said.

Noticed those blocks of color on the end of toothpaste tubes? Contrary to internet rumor, red does not mean “natural ingredients” and black does not mean “all chemicals.”

"It’s actually a marker for the machines when they’re manufacturing to know when to cut and fold the piece,” Boge said.

What about the concave circle on your milk jug?

“It’s for structural integrity. So when you drop it, if that wasn’t there, the milk would explode. But when you drop it, this pops out and it allows it to stay intact,” Boge said.

At the grocery store, some carts have small metal loops in the front compartment—they’re designed to hang bags from if you don’t want the contents being crushed by other bags. Margins on lined paper were originally designed to protect the writing from rats nibbling on the edge of the paper. And cedar hangers contain natural oils to help repel moths to keep your clothing safe.

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