So you've got your new jar of pickles. It's a glass jar, with a metal lid. The little saftey button on the lid is pressed down tight, ensuring that your pickled goodness is fresh. You go to turn the lid to the left...
The lid won't open! It's stuck on tight. No amount of turning, pushing, pulling, or towel-wrapping will open it. What are you going to do? Well, now, through equal parts black magic and physics, you can open your stuck jar with a minimum of fuss!
You will need:
Any reasonably solid object can count as the blunt object needed. The optimal solution is one of those kitchen knife sharpeners of the stout metal rod variety, but one can use a pocket knife in the closed position in a cinch.
Foremost in your mind should be the fact that the jar unscrews to the left. Hold the jar in your left hand and your blunt object in your right. Now, strike the lid with the blunt object in this specific manner: the object itself should be turned 45 degrees from the lid, such that you're striking the corner of the lid. The direction you're swinging the object should be just a little sharper than the tangent line to the lid (you want to aim in just a little from missing it entirely). Strike away from yourself, on the right side of the jar. The amount of force you want to hit it with should be just barely enough to dent the metal lid, which is not that much force at all. Don't go swinging wildly.
You want to do this three times, with each blow to the lid equally spaced around its circumference. The blows should almost just tap the lid, though it should get dented a little. Don't break it.
Now, here's where the black magic comes in. Go to open the jar... it should pop open practically as soon as you start to turn it. Pop!
This technique will work on almost anything with a screw-top. I've used it on empty pop bottles which were screwed tightly shut (so I couldn't recycle them), for instance. I'm really unsure of the physics behind this; my best guess is that you're pushing the lid just far enough that it becomes unstuck. I've done this like a party trick: no one can open the salsa jar, oh no! Out comes my Swiss Army Knife, bang bang bang, the lid pops open. Saved the party, got the girl, and ALL THIS CAN BE YOURS AS WELL.
TenMinJoe sez: re How to open a stuck jar: I think it works because it's the vacuum seal that is making it hard to open - if you deform the lid a bit with a good whack, then you only have to turn it a tiny bit and the air hisses in; vacuum seal broken, jar easy to open.