Bag of Eternal Stench
Our understairs cupboard started to stink. At first, it was just a light corruption in the air. After a month or two of summer, it was gas mask time whenever you wanted to retrieve a coat or shoes, so we decided to find out once and for all what it was.

After removing about half the items, one by one, suspicion homed in on a rather old fleece. In one pocket we found a plastic bag full of black liquid, clearly the source of the stench. A plastic bag, tied at the top, is pretty watertight, but not so airtight that noxious fumes will be contained. Slowly, they leak out, and if what they are leaking out into is a small cupboard, then nauseating stinkiness ensues. The Bag of Eternal Stench was immediately disposed of in the outside bin, but the mystery remained. What was it?

The answer came to us a few days later. In the spring, we had been to visit the horses at the local riding school and had taken some carrots with us. We ended up not using them, and as the weather then warmed up to the point where a fleece was not necessary, the fleece remained undisturbed in the back of the cupboard for months.

TL;DR - If you like carrots, don't read this.
( Amish Information Systems hates misplaced, commas, Tue 21 Jan 2014, 12:24, 2 replies)

I should have had this as the title of my story haha

(bumless The man with the hole in the middle, Tue 21 Jan 2014, 12:55, closed)

Indeed
Yours appears to be more eternal and more stench-worthy. At least we could simply stick the bag in the bin - which I understand isn't an option available to you. Sympathies.
( Amish Information Systems hates misplaced, commas, Tue 21 Jan 2014, 16:43, closed)