You're standing in your kitchen at 11 PM, staring at a pot of boiling water and a small piece of medical-grade silicone that costs forty bucks. It feels a little weird, right? Boiling something that’s been inside your body in the same pot you used for pasta sauce earlier is a unique "period owner" milestone. But honestly, knowing how to sterilise a menstrual cup properly is the difference between a product that lasts a decade and one that ends up in the trash after three months because it smells like old gym socks.
It’s about safety. It’s about pH balances. Most of all, it's about not getting an infection because you got lazy with the maintenance.
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Let's be real: the instructions that come in the box are usually pretty vague. They say "boil for five minutes," but they don't tell you what happens if you forget the pot on the stove and the water evaporates. (Spoiler: the silicone melts, your house smells like a chemical factory, and you're out $40). There's a lot of conflicting advice floating around the internet about vinegar, hydrogen peroxide, and those fancy UV cases. We need to clear the air.
The First Boil: Why New Cups Aren't Ready to Wear
Don't just rip that package open and shove the cup in. Even if the brand is high-end like Saalt, DivaCup, or Mooncup, it has been sitting in a factory. It’s been handled by machines and potentially humans. It might have microscopic residues from the manufacturing process.
You've gotta do the "deep clean" before the very first use.
Fill a deep pot with enough water that the cup can float freely. If it touches the bottom, the direct heat from the stove element can cause the silicone to degrade or even melt. A pro tip? Put the cup inside a metal wire whisk. This keeps it suspended in the middle of the boiling water, safe from the scorched floor of the pot. Set a timer for 5 to 7 minutes. Don't go over 10. Silicone is tough, but consistent over-boiling eventually makes the material brittle.
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How to Sterilise a Menstrual Cup Between Cycles
Once you’re in the rhythm of your cycle, you don't need to boil the cup every single time you empty it. That would be a nightmare. Imagine trying to boil a pot of water in a public bathroom stall. No thanks.
During your period, a simple rinse with cold water—to prevent staining—followed by warm water and a fragrance-free, oil-free soap is enough. But once the bleeding stops and you’re ready to put the cup away for the month? That’s when the real sterilisation happens.
- The Classic Boil: This remains the gold standard. It kills bacteria, viruses, and fungi. If you’re worried about the "pasta pot" factor, buy a small, dedicated stainless steel pot specifically for your cup.
- Steam Sterilisers: You might have seen those little electric steamers that look like egg cookers. They’re actually great. They use less water and usually have an auto-shutoff feature, which is a lifesaver for the forgetful among us.
- Milton Tablets: If you’re traveling or don't have access to a stove (hello, camping or dorm life), cold-water sterilising tablets are a solid backup. These are the same ones used for baby bottles. Drop a tablet in water, soak the cup for 15 minutes, and you’re good. Just make sure to rinse it well afterward because the chlorine smell can be a bit much.
The Problem With Soap
Most people ruin their cups by using the wrong soap. Anything with "moisturisers," "fragrance," or "oils" is the enemy. These ingredients leave a film on the silicone. That film traps bacteria against your vaginal wall, which is basically an invitation for a Yeast Infection or Bacterial Vaginosis (BV).
Stick to soaps specifically formulated for cups or a very basic, unscented glycerin soap. If you’re in a pinch, just use plain water. It’s better to use nothing than to use a scented body wash that’ll mess up your internal pH.
Dealing With Staining and Smells
After a few years, your cup might start looking a little... weathered. It turns a slight yellowish-brown. This isn't necessarily "dirty"—it’s just protein buildup and iron from the blood. It’s natural. But if it grosses you out, there’s a fix.
A soak in 3% Hydrogen Peroxide is the "secret" move the community swears by.
Leave the cup in a glass of peroxide for about 6 to 12 hours (overnight is easiest). It’ll come out looking brand new. Wait, though. You can’t do this every month. Hydrogen peroxide is an oxidizer; if you do it too often, you’ll shorten the lifespan of the silicone. Save this for a once-a-year deep refresh.
And the smell? If your cup has developed an odor that a boil won't fix, check the tiny suction holes near the rim. Use a toothpick or an interdental brush to clean them out. Often, a tiny bit of fluid gets trapped in there and goes funky. If it still smells, a quick soak in diluted lemon juice or white vinegar for an hour can help, but you must boil it afterward to remove the acidity.
Can You Use a Microwave?
Yeah, but be careful. You can buy microwaveable silicone bags or containers. You fill them with water, pop the cup in, and nuke it for a couple of minutes. It’s basically steaming.
Never just put the dry cup in the microwave. It will melt. Also, if your cup has any metal (like some older versions of the Lily Cup or certain generic brands), the microwave is a hard no. Check your brand's specific material list first.
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Don't Forget the Storage
Sterilising is useless if you then toss the cup into a plastic Ziploc bag. Silicone needs to breathe. If you trap it in an airtight container while it's even slightly damp, you’re creating a petri dish for mold.
Always use the breathable cotton pouch that came with the cup. If you lost it, a clean sock works surprisingly well in a pinch. Just keep it somewhere dry—not the humid bathroom cupboard if you can help it.
When to Stop Sterilising and Start Tossing
Eventually, even the best-maintained cup reaches the end of its life. Silicone doesn't last forever. You should inspect your cup every time you sterilise it.
Look for:
- A grainy texture or "chalky" film that won't wash off.
- Tears or cracks in the rim or stem.
- Persistent odors that survive a boil and a peroxide soak.
- Thinning of the material.
If you notice any of these, it’s time to say goodbye. Most high-quality cups like the DivaCup or Saalt suggest replacement every 1 to 2 years for "optimal hygiene," but many people safely use them for 5+ years with rigorous care. Use your best judgment. If the material feels "sticky," that’s a sign the silicone is breaking down. Throw it out.
Actionable Steps for a Clean Cycle
Maintenance shouldn't be a chore. If you want to keep your cup in top shape for the long haul, follow this rhythm:
- Pre-Cycle: Give it a 5-minute boil in a whisk to ensure it's sterile before it goes in.
- During Cycle: Rinse with cold water first (to prevent stains), then warm water and oil-free soap. Keep those suction holes clear.
- Post-Cycle: Boil it again, dry it completely in the open air, and store it in a cotton bag.
- Once a Year: Do a 6-hour hydrogen peroxide soak if you notice significant discolouration.
Taking these small steps ensures your cup remains a safe, eco-friendly, and cost-effective way to manage your period without any nasty surprises for your vaginal health. Keep it clean, keep it dry, and keep it away from the bottom of the pot.