Kilner® Jar Seal and Lid Care: A Simple Maintenance Routine

Quick answer

Wash glass jars and lids in warm soapy water, rinse and dry fully before storing. Check rubber seals regularly, replace any that are cracked, hard or stretched, and sterilise jars only when you are preserving food for long storage. A quick monthly check keeps clip top jars airtight and ready to use.

How often should you check Kilner jar seals?

Aim to check seals every few uses, or at least once a month if jars are in regular rotation. Run a finger around the rubber: it should feel soft and flexible, not brittle or flattened. If a seal has lost its shape or shows small cracks, it will not hold a vacuum reliably, so replace it before your next preserving session.

How to clean Kilner jars without damaging the seal

Remove the rubber seal and clip from the lid before washing. Warm water with a little washing-up liquid is enough for everyday cleaning; a bottle brush reaches the corners of facetted jars. Avoid abrasive scourers on the glass and never put rubber seals in a dishwasher, as heat can harden them. Rinse everything well and leave to air dry upside down on a clean cloth.

Do Kilner jars need sterilising?

Sterilising is only necessary when you are preserving jam, pickles or other long-keeping foods. For dry storage such as pasta, flour or biscuits, a thorough wash and dry is sufficient. To sterilise, wash jars in hot soapy water, rinse, then place them in an oven at around 120°C for 15 minutes or use a dedicated sterilising solution. Let jars cool before filling, and always sterilise the lids and seals too.

What to do when a seal no longer seals

If a clip top jar fails the vacuum test, first check that the seal is seated correctly and the clip is not bent. A worn seal is the most common cause. Replacement seals are inexpensive and easy to fit; simply stretch the new rubber over the lid rim. Keep a spare set on hand so you are never caught out mid-batch.

Storing jars between uses

Store clean, dry jars with the lid off or loosely placed on top to let air circulate. This prevents stale smells and stops the rubber from being compressed for long periods. Keep jars in a dry cupboard away from direct sunlight, and avoid stacking heavy jars on top of each other if the seals are still fitted.

Kilner jar care FAQ

How do I know if my Kilner seal needs replacing?

Look for cracks, hardness, stretching or a flattened shape. If the jar does not hold a vacuum after filling, the seal is the first thing to check. Replace seals as soon as they show wear.

Can I put Kilner jar seals in the dishwasher?

No. Dishwasher heat can degrade rubber, causing it to harden or crack. Wash seals by hand in warm soapy water and dry them thoroughly. Hand wash seals to extend their life.

Do I need to sterilise jars for dry food storage?

No. A hot soapy wash and complete drying are enough for dry goods. Sterilise only when you are preserving food that will be stored for weeks or months. Match the cleaning method to the food.

Useful Kilner products for this routine

• Kilner® Replacement Seals for 0.125 Litre Clip Top Jars: Kilner 6 Replacement Rubber Seals are suitable for Round Clip Top Glass Storage Jars and fit 0.125L jars. Having the correct size seal ready means you can replace a worn seal immediately and keep small jars airtight.
• Kilner Thermometer and Lid Lifter for Jam Jars: The Kilner Thermometer and Lid Lifter set combines two essential tools for preserving and pickling, with accurate measurements. A thermometer helps you reach the right preserving temperature, while the lid lifter makes it safer to handle hot jars during sterilising and filling.
• Kilner® Set of 3 Facetted Clip Top Jars 0.95 Litre: The Kilner Set of 3 Facetted Clip Top Jars 0.95 Litre features a distinctive design and is perfect for storing dried, preserved and pickled foods. These jars are a practical size for batch preserving, and their clip top design means the seals are easy to check and replace as part of your routine.