Smelly Jelly is a flame-free, water-based air freshener that resembles colorful crushed ice. You add fragrance oil and distilled water to a small amount of water-absorbing crystals, and the crystals slowly release the scent through a vented lid. The supplies are inexpensive and most of the steps are safe for a child to do, which makes it a good project to build with kids. Pick the fragrance oils and the color together, and let them make a jar for their own room. For other no-heat and beginner projects, browse the Step by Step Guides.
What You'll Need
What You'll Need
Check items off as you gather them
Supplies
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Water Crystals superabsorbent crystals (also sold as water crystals) that swell with water. Lone Star does not stock these, so source them from a craft, garden, or hobby retailer
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Fragrance Oil the source of the scent, from fragrance oils; about 1 tablespoon per jar
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8 oz Jars with Vented Lids straight-sided jelly jars and daisy-cut or vented threaded lids from candle jars; the vent lets the scent escape
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Distilled Water about 1 cup per jar; it keeps the gel from molding
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Food Coloring optional a few drops to tint each jar
Tools & Equipment
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Measuring Cup and Spoons a teaspoon for the crystals, a tablespoon for the oil, a cup for the water
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Stirring Utensil a spoon to blend each jar
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Wax Paper to protect the workspace; fragrance oil can discolor a wood finish, so cover the surface before you start
Skip ahead to the step-by-step guide
Why Distilled Water
Use distilled water, not tap water. Distilled water is boiled and recondensed, which leaves bacteria, minerals, and other contaminants behind[1][2]. Starting from clean water means the finished gel resists mold and mildew far longer, so a jar keeps looking and smelling fresh for weeks instead of clouding over. Tap water will work, but it carries the microbes and minerals that cut a jar's life short.
The Step-by-Step Process
Line the jars up like an assembly line and run each step across the whole row before moving to the next. The repetition makes it easy for a child to follow, and it keeps the measuring consistent from jar to jar.
How to Make Smelly Jelly
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1
Set up the jars
Lay wax paper over the workspace and line the open jars up in a row. Working down the line one step at a time keeps every jar even and gives a young helper an easy rhythm to repeat.
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2
Add the water crystals
Spoon about one teaspoon of crystals into each jar. That looks like almost nothing, but the crystals absorb many times their weight in water, so a teaspoon fills an 8 oz jar once fully hydrated. Do not add more.
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3
Pour in the distilled water
Measure about one cup of distilled water into each jar. An adult should handle the heavy water jug. The crystals begin to swell almost immediately.
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4
Add the fragrance oil
Measure about one tablespoon of fragrance oil into each jar and stir slowly. The oil sits on the surface at first and blends in as the crystals plump. An adult should handle this step, since undiluted fragrance oil can irritate skin.
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5
Tint and stir
Add a few drops of food coloring to each jar and keep stirring for a couple of minutes. The color spreads evenly through the water and a child can watch the crystals swirl as they grow.
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6
Cap with a vented lid
Screw a daisy-cut or vented lid onto each jar. The small holes let the aroma escape while keeping the crystals contained inside. For a jar you plan to move or gift, a cardboard pulp liner under the lid seals it for transport.
Where to Put Smelly Jelly
Because smelly jelly needs no heat and no flame, it goes places a candle cannot. Set a jar on a nightstand, in a bathroom, on a desk, or in a cup holder in the car. Each jar holds its scent for several weeks. When the crystals dry out, stir in a little more distilled water to bring it back; when the scent fades, add a few more drops of fragrance oils and stir.