Last summer, I played in a tournament called the Danbury Amateur, along with several other guys from my club. We got two rounds at Richter Park, a semi-free lunch each day, and a really nice insulated water bottle, which I used for the rest of the golf season.
I forgot about the water bottle during the winter, though, and for several months it rolled around in the trunk of my car, along with a golf-ball box containing six or seven loose golf balls. The water bottle and the ball box made quite a racket when I cornered hard, etc., but as soon as I had parked my car in my garage they stopped rolling around and I forgot about them.
This spring, I put my golf clubs back in the trunk, and brought the water bottle inside my house, to refill it. When I opened it, I noticed that there was a little bit of water still in it, from last year, and suddenly I wondered whether anything bad would happen to me if I drank the leftover golf water instead of pouring it out.