Open a Stuck Jar With a Knife Pt. 2

About: I like to make things for the internets. I also sell a pretty cool calendar at You'll like it.

I recently made an Instructable showing how I loosen jar lids with a knife. Commenters pointed out that this method would likely put shards of glass in your food and that there was another way to use a knife to loosen a lid.

The result? It works! Mostly. It's also just as easy as the other technique so by knowing both you should be well on your way to being a ninja with the jam jars.

Step 1: Get the Knife in There

Work the tip of a table knife into the gap between the lid and the jar.

Step 2: Twist and Pop

Twist the knife like you're turning a screwdriver. If it works you'll hear a very satisfying POP as the seal breaks. Opening the jar after that is incredibly easy.

I only bought two jars to test because I already had some extra jam for the last test and now I have two more than that. Anyway, one worked fantastically and the other didn't work at all.

So keep both techniques in mind and you'll find no jam jar that can resist you.



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    7 Discussions


    2 years ago

    Ed, I recommend doing like this:

    1:First take a Sharp Knife, And a jar of jam.

    2:Hold the sharp knife properly and "BOOM" stab it on the lid of the jar.

    3:Twist the lid with some force.

    4:And there you go...

    2 replies

    3 years ago

    Glad you did the part 2 as that was going to be my comment on part 1!

    I do it slightly differently though and it's worked for me 100% of the time. Turn the jar upside down then insert the knife (or spoon - never tried it but I guess it'll work as well) into that crack. Having the jar upside down makes it even more visible. Then just pull the knife outwards slightly (I don't turn/twist it) until you hear that crack. Even with fluid contents I've never had an issue of leaking because you've just broken the seal but the bottle is still closed as such. And IIRC it would even work with your second bottle as you can push the knife blade in deeper, and the pulling outwards part is such a small movement that the thicker rim of the jar shouldn't give you any issue and you'll still manage to break the airtight seal.

    Hope you give it a try and report back with the (maybe final) part of the trilogy!


    3 years ago

    What works better than a knife blade is a spoon, the spoon portion not the handle placed under the edge of the jar top. You don't have to twist it just pry up the edge ever so slightly. Once the air tight seal is broken it will easily open. Another good way to lose the top is run it under hot water for a minute or so to expand it making it easier to open.