Odd behavior... on my first day, I didn't realize Flint tools could be repaired by placing one flint into a crafting table with the tool. So I made 5 Flint pickaxes before I realized this. I threw the extra pickaxes on the ground behind my house to get rid of them, but an hour later, they were still there. They will not de-spawn! So I just threw them into a chest (there's no ExtraUtilites mod with a Trash Can in this modpack).
Today, I finally got sick of them taking up space, so I hiked over to a lava pool I had discovered, and stood on the edge and threw them all into the lava. And they all bounced around on top of the lava until they landed on a stone block, and that's where they all stayed.
The amazing, indestructible, non-despawning Flint Pickaxes! I'm laughing out loud, I just find it very funny. Not even lava can destroy them!
Yeah that has been a feature of Tinker's for a while now. There are a couple of ways to get rid of them in this pack. The Viod Chest, the Viod Bag, and the Viod Pipe will all delete any items put/piped into them