Do You Know What’s in Your Walls?
Last updated February 13, 2026
Last updated February 13, 2026

If your walls could talk, what would they say? Would asbestos be present in the materials? Would rodents or bats be scurrying or flying around? If you have critters in your walls or thousands of snakes like one Idaho couple, you should probably call the exterminator. But what if you find money or hidden treasures? What if you found bones like in the Holden Chapel at Harvard University? Hopefully, the only thing hiding behind your sheetrock is poor insulation—we can help you with that!—but let’s talk about some crazy things people found hiding in their walls.
Mummified Cats
It sounds odd, but hiding cats in the walls of your home is an ancient ritual that was popular in the UK. Hiding cats was supposed to send evil spirits running.
Urine and Fingernail Clippings or “Witch Bottles”
The most recent case of this was documented in 2009 in Greenwich. When urine and fingernail clippings were combined in a bottle, they were called “witch bottles.” They were hidden in homes to counter the curse of a witch.
Art
From murals painted by the famous Keith Haring and unsigned Van Goghs, to jewelry, figurines, archaeological treasures, Mayan murals, and sought-after comic books, there are countless stories of literal hidden gems behind the walls of people’s homes.
Cash
Wouldn’t you love to find money in your walls? A contractor who was renovating a bathroom in Ohio found $182,000. Apparently, the money was hidden during the Great Depression by the original homeowner. In Illinois, a mobster (and hitman) hid jewelry and firearms along with his cash. The loot was found after his 2007 trial. And these aren’t the only stories of finding hidden cash. One man in Utah even gave the money he found back to the previous homeowner.
Dirty Underwear
You’d probably much rather find cash behind your sheetrock, but it’s so common to find worn underwear behind walls in Western European homes that people don’t even report it anymore. Treasures are often wrapped inside the garments. Much like the cats and witch bottles, the garments were supposed to ward off bad spirits.
Love Letters
One pair of siblings found a box of love letters between a World War I soldier and his wife in their walls.
Forget, “What’s in your wallet?” We want to know what’s in your walls!
And please don’t try to insulate your walls with underwear or any other non-traditional insulation materials—let us help you take care of your insulation problem instead! Hopefully we don’t find any hidden cameras, snakes, bones, or secret corridors. Although a secret corridor would be pretty cool, wouldn’t it?
Get a free energy audit and discover how much you could save on your utility bills.
Get Your Free QuoteOwner & Founder
Chris didn't start RetroGreen Energy because he wanted to be in the insulation business. He started it because he wanted to fix homes the right way.
After earning his BPI Building Analyst certification and Minnesota Building Contractor license, Chris spent years studying how homes perform as systems. He saw firsthand that most comfort and energy problems weren't caused by old windows or outdated furnaces — they were caused by air leakage and inadequate insulation that nobody was diagnosing properly.
In 2009, he launched RetroGreen Energy with a commitment to doing things differently. Every project would start with proper diagnostics. Every recommendation would be based on data, not sales targets. And every homeowner would get the honest truth about what their home actually needed.
READY TO SAVE?
Join hundreds of Minnesota homeowners already enjoying lower utility costs with RetroGreen Energy.