How To Clean Sippy Cups: A Step-By-Step Guide to Keep That Mold Away!

Spill-proof sippy cups are quite possibly one of the most favored and most utilized inventions by parents today. Tots around the world tote their cups everywhere they go, all while keeping the mess contained. A product that prevents one less mess for a parent to deal with is always welcomed.

Every good thing usually has its downsides, though – and unfortunately, these little cups have been found to be the perfect breeding ground for mold and bacteria to grow.

Baby boy sitting in a high chair, drinking form his blue colored sippy cup

A few years back there was a certain brand that was growing black mold inside a hidden part of the cup. Worried parents posted and shared pictures on social media resulting in an internet frenzy. The company producing these cups quickly released an apology and recalled 3.1 million units of their cups.

This little incident had parents wondering if sippy cups were still safe to use. The answer is yes. However, we need to know how to properly clean the sippy cup so that we can prevent mold and bacteria from growing inside.

In this article, we will discuss how and where mold grows, the dangers of your baby ingesting it, and the substances that kill mold.

We will also go through the steps needed in order to properly clean your child’s sippy cup to keep them safe and prevent mold and bacteria growth if placing it in a dishwasher basket and popping it inside the machine to do its work is not enough of a solution.

After reading through this article and following the outlined steps, you will be able to rest assured that your child is drinking from a SAFE and spill-proof cup.

What is Mold Anyway?

Mold is a type of fungus that grows best in warm, moist environments containing “food” for it to feed on.

The sippy cup has all of these mold growing qualities and then some. With all of its valves and straws, the mold has plenty of places to hide and thrive if not cleaned properly.

Mold spores are everywhere, they float through the air searching for the ideal place to grow.

What Makes Mold In Sippy Cups Dangerous?

Not all molds are dangerous. However, in some children, mold will cause an allergic reaction.

Symptoms of a mold allergy are a runny or stuffy nose, sneezing, watery eyes, cough, and itchy eyes, nose, or throat. Mold ingestion by a child who is very allergic to mold could also suffer from respiratory distress.

Other molds may give off a toxic substance that could make your child sick. They may experience an upset stomach, nausea, or diarrhea. In extreme cases, they may also get food poisoning.

What Substances Kill Mold In Sippy Cups?

The following are considered safe solutions to clean mold out of sippy cups. Use one of these methods to clean your child’s sippy cup when you see mold growing in or on its parts – and at least once per month to prevent mold growth:


Using white distilled vinegar to clean mold in a sippy cup is a great choice because it is a natural and inexpensive option that works well.

Studies have shown that white vinegar kills 82% of mold species along with other viruses and bacteria.

To clean a moldy sippy cup with vinegar simply spray the visible mold with undiluted vinegar, then soak in a vinegar solution (1-2 T vinegar per cup water) for 15 minutes.

Baking Soda/Water

Baking soda is another cheap and safe way to clean mold from your child’s straw cup.

Not only will the baking soda clean and disinfect, it will also get rid of nasty odors that tend to cling to a forgotten sippy filled with milk or juice.

Since baking soda is such a mild cleaner, it will deodorize without leaving behind a strong scent of its own.

To clean your sippy cups thoroughly using baking soda you will need to take the cup completely apart and soak overnight in a mixture of ¼ cup baking soda and 4 cups of warm water. You can also use a baking soda/vinegar mixture for extra fungus fighting power.

Hydrogen Peroxide

Hydrogen peroxide provides a triple threat with its antifungal, antiviral, and antibacterial properties.

Peroxide is inexpensive, safe, and an effective cleaning method. It is better than bleach solution because it doesn’t emit poisonous fumes and is considered safe for the environment.

If you choose to clean your child’s sippy cup using hydrogen peroxide, disassemble the cup completely and use the 3% solution to soak the moldy parts in for 10 minutes.

You may have to scrub the mold stains after soaking. After the soaking and scrubbing actions are complete, you should rinse and dry thoroughly.

Like baking soda, hydrogen peroxide can also be mixed with vinegar for a more effective mold killing solution.

Grapefruit Seed Extract And Water

This natural mold cleaner is the most expensive, but is also considered highly effective.

It has virtually no odor, so it won’t cause the liquids you put in the cup to become flavored by a strong odor left behind.

To clean your cups using this method, mix 10 drops of grapefruit seed extract per cup of water in a spray bottle. Spray all mold stains with this solution and scrub with a toothbrush. Let it dry. Once it dries, you can rinse and dry thoroughly.

To sanitize the cup, you can soak all parts in this same solution for 10-15 minutes.

Bleach/Water Mixture

This method would personally be my last resort for cleaning mold stains in my child’s sippy cup.

Although the solution recommended is considered safe by professionals, bleach is a harsh, toxic chemical that should be used sparingly and thoughtfully.

Before using this method, you should wear rubber gloves and mix the solution in a well-ventilated area.

You can sanitize your sippy cups with bleach by taking the cups apart and soaking them for 2 minutes in a mixture of 2 teaspoons of bleach per gallon of water. Rinse well and air dry thoroughly.

How Can I Properly Clean a Sippy Cup?

In order to ensure that your child’s sippy cup is safe for use and to prevent mold and bacteria growth, there are certain steps that should be followed.

Before you begin to wash the cup, know that it would be best to try and purchase cups that are easy to take apart and have fewer parts involved. The more complicated the cup is and the more parts it has makes it easier for mold to hide and grow in all the tiny parts and crevices.

Another preventative tip to take note of is to always try and rinse out your child’s sippy cup when it is not in use, especially when it has had milk or juice in it. This helps to prevent mold growth before you get the chance to thoroughly sanitize it.

Here’s a list of steps for you to follow.

Step #1

First, you need to completely take the straw cup apart.

The small parts that prevent spills are the ones that are most likely to grow mold, so be sure you have access to every nook and cranny.

If you need to, read the instructions and even consult the manufacturer about this. Some cups even come with directions and special brushes to help you clean their specific brand of cup.

Step #2

Now that you have all of the parts disassembled, dump them in a bowl full of very hot water and a little bit of dish soap. Filling the sink with water and leaving these parts to float inside isn’t recommended, as there’s likely to be germs that may contaminate the water.

Let the parts soak for 10-15 minutes. This soak will disinfect and make it easier to clean any stubborn stains, curdled milk, or food particles that are stuck on the cup or its parts.

Step #3

Next, find your best scrubbing tools (but make sure they’re clean first) and thoroughly clean every part.

Use a fresh, clean dishcloth to clean the biggest parts. Do not use a dishcloth or sponge that you have been using around your kitchen. You will only be transferring bacteria to your cups as these tend to hold bacteria and odors when they have been used.

For the smaller parts, you will need to use a small scrubbing brush to clean them. You can use a STERILE toothbrush, dental brush, nipple brush or bottle brush, toothpick, pipe cleaner, or q-tip to clean inside the straws and tiny openings of the sippy valves and lids.

In order to get inside the small openings of these valves and straws with these tiny tools, you will need to pinch the plastic around its opening.

Step #4

After you have cleaned and inspected every part for cleanliness, dump the soapy water down the drain and replace with clean, hot water.

Rinse your dishcloth and any brushes used.

Let the parts soak for 5 minutes then use your clean cloth and brushes to remove any soap residue that may have been left behind. Soap residue is favorable for mold growth so you want to be sure you rinse it off well.

Step #5

This step is optional, but it is recommended to sanitize your child’s sippy cups once per month.

You can use the cleaning solutions and methods we mentioned earlier in the section that lists the substances that safely and effectively kill mold.

You can also use a bottle sterilizer for this purpose, and if your baby was bottle fed you may already have one of these. You can use a stove-top sterilizer, microwave sterilizer, or a micro-steam bag. The latter two both use your microwave to produce steam that kills all the bad stuff.

If you don’t have or don’t want to buy any of these then you can simply dump the cup and all of its parts in a pot of boiling water for 5 minutes and voila, the cup is sterilized.

Step #6

Lastly, you want to be sure all of the parts are completely dry before reassembling the cup.

Remember how we talked about how mold loves to grow in warm, moist places? When you reassemble a cup that has just come out of a hot water rinse and shut the lid, you’re creating a mold haven.

The best way to dry your child’s cups is to dry them on a drying rack. This is more sanitary than drying them with a dish towel, setting them on the counter or a dish towel to dry.

All of these have the potential to contaminate the cup with germs or trap moisture inside the cup and lid.

Bonus Step #7

One last cleaning tip to try because it’s easy, cheap, and fun!

Let your kiddos plop a few denture tablets into a bowl filled with water and their sippy cup parts. The kids will love watching the fizzy action and you will love the clean results.

This little hack is particularly helpful at eliminating any lingering odors in your child’s cup.

Wrapping It Up

It’s important to keep your child’s sippy cup clean because these little cups can harbor harmful bacteria and mold if not cleaned properly.

Mold can be dangerous when ingested because it can cause allergic reactions and in some cases, release toxins that can make your child sick and more vulnerable to illnesses.

Some substances are known killers of mold and are safe to use to clean items like sippy cups and bottles.

Vinegar, baking soda, and hydrogen peroxide are the most cost-effective and safe substances you can use to clean and sterilize your child’s sippy cups.

The grapefruit seed extract solution is also a safe and highly effective method for sanitizing your cups but you will find it to be more expensive than the other options.

Lastly, the bleach/water option is considered safe by professionals in the proper ratios – however, it is a very harsh chemical that should only be used with care.

These are the simplified steps we laid out in the article so you can be sure you’re properly cleaning your child’s sippy cup.

  • Buy sippy cups with fewer parts and are easy to take apart
  • Rinse cup when your child is done using it
  • Completely disassemble cup
  • Soak in HOT, soapy water for 10-15 minutes
  • Scrub cups and parts thoroughly with a dishcloth and the appropriate sized brushes
  • Soak in HOT clean water for 5 minutes
  • Sterilize your cups, using one of the methods recommended, at least once per month
  • Allow cup and all parts to drip dry thoroughly on a drying rack before reassembling

Next time you encounter a nasty, stinky sippy cup filled with dried curdled milk, you’ll know exactly what to do. For now, you can rest easy now that you know how to eliminate the toughest stains and stenches in your child’s sippy cup!

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