…how long you think that would last tightly sealed?
Well here are some WAGs.
Farts are comprised of gas and little tiny pieces of shit. Now as far as I know, a typical fart does not involve a very large amount of gas, so the contents of the jar would probably be mostly air. Unless you used a small jar or had a particularly big fart. You’d also have to figure out a way to get the fart into the jar and displace the air and put the top on without any leakage.
Now I think most of the tiny pieces of shit involved would eventually fall to the bottom of the jar, though I don’t know how much they contribute to the over all odor.
No PROBLEM! You could take a small jar and lid underwater into a pool with you, hold jar upside down, fart, and catch the raising bubbles of fart into your upturned jar! Gas displaces the water. Cap it and return to surface. 100% fart in a jar!
Just don’t light a match…
A year, tops.
And that’s in a brown jar kept out of sunlight.
You should check the expiration date at the edge of the label.
I think a balloon and a plastic tube, ah, properly inserted would make a much more efficient fart-catching device. I don’t know how the subsequent enjarment would be accomplished. If you could create enough of a vacuum to draw the fart into, you could probably store the fart indefinitely.
First, you tell us that your feet smell like cornchips.
Now, you express an interest in containing your farts.
Why, Whammo, why?
What would you do with them? Aromatherapy for Real Men? Glade Plug-Ins for the Weirdo in your life?
I really like you, Whammo, but you are really beginning to worry me. 
Persephone - the dude nearly paralyzes himself with weed and you’re worried about farts in a jar?
Whammo, I think you’ve got the makings of a brand new hobby. Start saving all your farts in Ball Dome Jars and labelling them with the date and what you had for breakfast that day. Sell them or give them as gifts to your associates. Next thing you know, they’ll have collectible value. Then watch as an entire Whammo-fart-trading hobby springs up. Rich snots from the yacht club will start trading Whammo farts. Marvin Shanken will launch “Flatulence Aficionado” and will list Whammo’s 2000 vintage farts as the pinnacle of the hobby. Some aristocratic douchebag with too much money will buy a six-pack of Whammo 2000 farts at a Christie’s auction for $10.6 million, the most ever paid for a six-pack of farts at auction. Whammo, of course, will make a load of dough and will stop talking to us.
C’mon - none of you saw this coming?
THespos: I know what he did with the weed! But man, most people get a bad buzz at least once. That’s not weird.
Farts in a jar, on the other hand, is really freakin’ strange.
if you managed to acheive it, you could put one of those countdown-string things they have in cartoons inside, then you could use it as a grenade.
“Sir! We have an extremely large grenade falling at high velocity directly above us!”
“Wait…that’s not a grenade…it’s a…FART IN A JAR! EVERYONE RUN!”
Unfortunately, I have first hand experience with this.
Check out this thread.
If you froze the fart-in-a-jar, would it help it’s longevity?
If you’re going to the trouble of catching your farts in glass containers, how about including a little diorama? You know, like the things with the fake snow in them? Then you’d have a collectible.