Leave it. Most times its just been cached and the owner is nearby. I have found valuables though - two cameras both in places they shouldn't have been, no owners near. One found its way back to its owner on the way out on the trail, the other to the Forest Service office, never heard any more about it.

Some scenes get eerie though. There's a place along the Duckabush River on the Olympic Peninsula called five mile camp, where someone was long-term camping one winter, with a tent and tarp and lots of gear laid out. I saw him and his camp twice, the third time I was back and he was gone, but al his stuff was still there, some of it knocked over and gathering rain and pine needles. His tent and sleeping bag hadn't been slept in for a while. Reported the gear to the Forest Service, they already knew about it. A trail crew picked it all up and hiked it out. A couple months after that we were back at five mile camp, and under a large rock we found some of his cooking gear still left behind. No idea where he went, up the trail to his winter fate or back down the trail to find a job, who knows. Folks who don't know about the camp will talk about the scene as being kinda spooky though.