What do Jem and the narrator find?

Jem and Scout find small gifts in the knot-hole of the Radley's tree.

As we came to the live oaks at the Radley Place I raised my finger to point for the hundredth time to the knot-hole where I had found the chewing gum, trying to make Jem believe I had found it there, and found myself pointing at another piece of tinfoil.
“I see it, Scout! I see it-”