Do you remember all the great stuff you used to have in your pockets as a kid? Sure, your mom called it "junk" and threw most of it away, but in your mind, there was a lot of quality material in there. Most of it served no purpose other than to stimulate your imagination (how many little boys still see a pen cap as a rocket or a stick as a gun?), but that was the purpose.
I still have stuff in my pockets. My wife has stepped in as my mother by calling a lot of it "junk" and throwing it away. The difference is now I see much of the stuff I find in various odd places are things that can be created and not just figments of my imagination. Right now I have in my possession two hotel card keys, 1" PVC pipe scrap, a lighter and a zip-type plastic bag. To the untrained eye, it may appear you can do nothing with these items (except the lighter), but I disagree.
Essentially, our pockets often become storage bins for all kinds of odds and ends that may have some use for. Plastic bags are good for storing things. Hotel card keys (or any plastic card) can be good separating tight plastic seams like those on a TV remote. Lighters are good for fusing objects. I don't quite know what to make of the PVC yet--a set of plastic napkin rings perhaps?
Whatever you feel the need to put into your pockets, there's a good chance you can make something out of it. These "microprojects" inspire the same creative urge, just on a smaller scale. Empty your pockets right now. What can you make?