What is the best way to open a tightly fitted lid of a jar?

Go around the edges, tapping the rim with the handle of a butter knife (leaving little dents). That should allow you to twist it off.

In future, if you're using a jar that you'll be emptying (like pasta sauce), the quickest way to open them is take a sharp, sturdy, pointed knife (or even a screwdriver), brace the jar well in a cloth, then carefully make a hole in the top of the lid (just place the point on it and give it a tap or two on the end of the handle). This breaks the seal of the jar, which is what makes it hard to open.

Ok - finally got it open! While googling, I came across a suggestion to cover the lid with a plastic glove and use that for traction. Not sure if it was the combination of running under hot water + the glove, or if the glove would've worked on it's own, but it's open now :)

One thing that has worked for me is to slide a flat (butter) knife along the glass under the edge of the lid. Turn slightly to break the seal. Warning -- if your knife isn't strong, it will twist the blade. You'll know if you got it, since you'll be able to hear the seal breaking

My favorite jar opener:

The Brix JarKey

You just need a gentle lift to let a little air in and then you can remove the top bare-handed. The lid is not damaged (unless you use more force than necessary).

In a pinch, you can use channel-lock pliers to do the same thing. Hold the pliers "upside-down" so the longer jaw is under the edge of the jar lid and the other jaw is against the top and gently lift. A little air leaks in just as with the JarKey and then you easily open the jar by hand.

You need to depressurize it. It is very easy to do to simply take the pointed edge of a fork and jab the top of the container (the tin lid). Any small puncture made will work, once done the lid will open normally without any strenuous force. This method will work in the case where traction cannot force the lid open.

Either (1) Tap around the lid with a hammer/meat pounder or (2) Grab the lid with a rubber glove and twist.

I've had success with 2 methods .. 1: Tap the lid on the edge of a worktop, working all the way round. 2: Either hold the top of the jar under running hot water or stand jar upside down in a bowl of hot water for a couple of minutes. (failing that I shout for son or husband!!).

I use a pipe wrench -- plenty of leverage for opening even the toughest jars.

Other suggestions would be:

• Turning the jar upside down, and using the palm of your hand to thwak the bottom a few times.

• Using a rubber band instead of a rubber glove, if you don't have one available.

Put a rubber band around the lid of the jar, grip firmly, and twist.

The OXO Good Grips Jar Opener works well for me. I have arthritis in my thumbs of all places.

use a butter knife and stick it in between the side of the lid and the jar. Pry it away from the jar a bit, and this should let air inside, making it incredibly easy to open (since there's no vacuum anymore)

Sometimes the vacuum in the jar causes a lot of friction between the lid and the jar. Holding the jar upside down and banging a few times on the bottom with your palm can get some air inside and free the lid.

For a few years I have used a Culinare One Touch Jar Opener. I bought one for my grandmother who was too weak to open jars herself and she loved it, and as I have a touch of RSI, thought I would get one for myself, it can open pretty much any straight sided jar - tad noisy, but very effective! (Amazon)

If you want to open a jar keep it in boiling hot water as glass is poor conductor of heat it will contract and the lid will expand and your jar would be opened