Unbeknownst to me, that bag was made of "degradable" material, and it had spent all this time out in the open, exposed to light and oxygen. Although it looked no different than when I first brought it home, the plastic disintegrated upon contact, producing a flurry of confetti-like bits. Not fully grasping what was happening, I grabbed the bag to see what it held. That was a very big mistake.
There were plastic flakes everywhere, and every one I touched shattered into smaller pieces. Observing they were somewhat electrostatic, I wasn't going to risk going after them with a bagless vacuum cleaner. Unsure of how best to proceed, I went with the first thing that came to mind: I fetched my tape sealer, and started using one-foot strips of package sealing tape as an impromptu lint roller. The adhesive wasn't quite as sticky as I'd like, but it seemed to get the job done. After about half an hour of this, I'd managed to pick up nearly all of the stray bits.
There are people who complain about plastic that lives forever, not understanding that if degradable material ends up in a landfill and gets buried under a ton of debris, it's not going to break down. Like so many misguided schemes (*cough* DRM *cough*), this is one that doesn't really serve its alleged purpose, and merely frustrates and annoys innocent consumers. Just give me eternal plastic, along with ways to recycle or otherwise dispose of it in an environmentally-acceptable manner once it has outlived its usefulness.