How to Replace Kilner Rubber Seals on Clip Top Jars

By Kilner® - Iconic Glass Jars, Bottles & Equipment | Kilner® | Published: 2026-10-30

Category: Tips & Care

Learn when and how to replace Kilner rubber seals on 0.35–2 litre clip top jars for a reliable, airtight seal every time.

Quick answer

Replace the rubber seal on your Kilner clip top jar when it loses flexibility, shows cracks, or fails to create a vacuum. Use the Kilner Rubber Seals pack for 0.35–2 litre jars and follow the simple steps below.

Why the right seal matters

The rubber seal is the only part of a clip top jar that creates an airtight barrier. Over time, repeated washing, heat exposure, and natural ageing make the rubber stiff or brittle, so it no longer presses evenly against the glass rim. A worn seal can let air in, which shortens the shelf life of preserved food and reduces the crispness of stored dry goods.

Kilner rubber seals are designed specifically for the brand's round clip top jars, so they match the groove and rim shape precisely. Using an off-brand gasket may look similar but can fail to seat correctly, leading to frustrating leaks or failed seals.

When to replace the seal

There is no fixed calendar for replacement because usage and storage conditions vary. Check the seal each time you open a jar. If it feels hard, has visible cracks, or leaves gaps when you close the lid, replace it before the next use.

If you notice that jars no longer 'pop' when opened, or liquid leaks during water-bath processing, the seal is likely past its best. Replacing it is a low-cost fix that prevents wasted food and frustration.

Step-by-step replacement guide

Remove the old seal: Open the jar and lift the old rubber seal out of the groove in the lid. If it is stuck, gently pry it with a blunt knife or your fingernail. Common mistake: pulling too hard can tear the seal and leave bits behind. Check the groove is clean before fitting the new seal.
Clean the lid groove: Wash the lid and groove in warm soapy water, then dry thoroughly. Any residue or moisture can prevent the new seal from sitting flat. Common mistake: skipping this step can cause the seal to slip out of place.
Fit the new seal: Press the new Kilner rubber seal evenly into the groove all the way around. It should sit snugly without twisting. Common mistake: forcing a twisted seal creates a gap that breaks the airtight closure. Run your finger around the seal to confirm it is seated evenly.
Close and test the jar: Place the lid on the jar and clip both wires down. Press the centre of the lid – it should feel firm with no movement. For a stronger test, fill the jar with water, close it, and turn upside down to check for leaks. Common mistake: assuming the seal works without testing can lead to spoiled contents later. If the lid moves or leaks, remove the seal and reseat it before use.
Store spare seals properly: Keep unused seals in a cool, dry place away from direct sunlight and heat. Common mistake: leaving spares near a stove or radiator makes them age faster. Rotate your spare stock so older seals are used first.

Product fact

Rubber Seals For 0.35 2 Litre Clip Top Jars - Pack of 6: The Kilner Rubber Seals pack of 6 fits 0.35, 0.5, 1, 1.5 and 2 litre Round Clip Top Glass Storage Jars. One pack covers all your small to medium clip top jars, so you can keep spares on hand without guessing sizes.
Rubber Seals For 0.35 2 Litre Clip Top Jars - Pack of 6