So... I generally carry a bag dedicated to trash while hiking/backpacking.
But this past weekend, Basilbop was off on a cross-country adventure while I took the trail, still nursing my ankle. On his travels, he found several balloons. At least one of them was a mylar balloon he stuffed into his pants' cargo pocket. I just spent waaaay too long trying to get all the mylar dust out of his pocket. Never seen the stuff disintegrated like that before. Really fine dust and very small bits. It seemed to sink into the garbage can as I tried to brush it off the inside of his pants pocket. Too late, I hoped I wasn't breathing it in. Stuff was almost as bad as styrofoam, very static clingy.
Best to carry a bag dedicated to trail trash and put things in that.