What’s this? Found under a bathroom vanity during remodeling—small glass tubes, 2 inches long, filled with liquid. Any ideas?

 

🧪 What Are These Mysterious Glass Tubes Found Under a Bathroom Vanity?

Home remodels often come with surprises — some exciting, some puzzling, and some downright weird. But few things spark curiosity like finding small, sealed glass tubes filled with liquid hiding beneath a bathroom vanity.

If you've come across these during your renovation project, you're not alone. Many homeowners and contractors have stumbled upon similar finds and asked the same question:

👉 “What are these things, and why are they here?”

Let’s break it down.

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🔍 A Description of the Mystery

Here’s what’s typically reported:

• Size: About 2 inches long

• Material: Clear glass

• Contents: Some kind of liquid inside, often clear or pale yellow

• Location: Hidden under or behind bathroom vanities, cabinets, walls, or flooring

• Quantity: Sometimes just one, often several

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🧪 Most Likely Answer: Mercury Switch or Thermometer Parts

The most common explanation? These small glass tubes are fragments of old mercury switches, thermometers, or even thermostatic devices.

Here’s why:

• Mercury switches were once widely used in wall-mounted thermostats, electrical components, and older appliances.

• Thermometers or barometers in older medicine cabinets or bathroom fixtures sometimes contained mercury or alcohol-based liquids.

• As these devices broke, or were discarded, parts could have ended up behind vanities or within walls — especially during prior renovations or when fixtures were replaced.

Caution: If the liquid inside is metallic and silvery, it could be mercury, which is toxic and should be handled with care.

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🧴 Other Possibilities

If the tubes don’t appear to contain mercury, a few other explanations could fit:

1. Perfume or Sample Vials

Some vintage perfume samples came in slim glass ampoules sealed with wax or corks. If your vanity once doubled as a makeup station, these could be old cosmetic samples.

2. Essential Oils or Homeopathic Remedies

Homeopathic remedies, especially those from European or holistic brands, often come in small sealed glass vials.

3. Medical Sample Tubes

Some medications, like injectable vitamins or old vaccines, were once packaged in small sealed glass ampoules. Unlikely in a bathroom, but not impossible.

4. Decorative Glass Fillers

Rare, but some old vanities used glass tubes filled with colored liquids as part of a decorative or novelty design. Think 1970s/80s.

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⚠️ Safety First: What to Do If You Find These

• Do not break them open. If the liquid is mercury or a chemical, it can be hazardous.

• Handle with gloves and keep them out of reach of children and pets.

• Check for markings — sometimes labels or etched codes can give clues.

• Dispose responsibly — if you suspect mercury or unknown chemicals, contact your local hazardous waste disposal center.

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🧠 Still Unsure? Here’s What You Can Do

• Post a photo online in renovation or mystery item forums (e.g., Reddit’s r/whatisthisthing).

• Ask your contractor — seasoned pros have seen a lot and may recognize it.

• Take it to a local hardware store or chemist for more insight (in a sealed bag).

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Final Thoughts

Finding strange items during home remodeling is more common than you think — and while some discoveries are treasures, others are simply relics of old construction, technology, or habits.

Those little glass tubes under your vanity? Most likely harmless leftovers from decades past. But they definitely make for an intriguing mystery — and a good reminder that every old home has its secrets.