I wouldn’t pick up water bottles or articles of clothing for reuse but I would probably pick them up for disposal. Other items, however, are fair game. I seldom find money but the best thing I’ve ever found was 2 fly rods with reels and line in a fly rod case. One was a St Croix 5 wt...kind of hohum...but the other one was a G. Loomis 2 wt which I still have and use. It’s a great rod and makes even the smallest fish feel like a whale. I’ve even caught a 15” bass on it which was like snagging Moby Dick!