nail karma
The act of looking for and picking up nails, screws, and other sharp objects when walking near or on streets and alleys, so as to help prevent oneself and others from getting flat tires. For best results, track your progress by keeping all found nails, screws, etc. in a jar.
I used to get a lot of flat tires until I discovered nail karma. I have two jars full of nails I've found!