New Recipe: Switch Tokens

Slot Token < --- > Class Token
Simply done!

Possible (subjective) example of the recipes:
Some Slot Token + Same slot weapon, any Class --> the Token of this Class
Some Class Token + Same class weapon, any Slot --> the Token of this Slot

SPUF thread

"possible solution on how to make the metal even more useful"

Just imagined how it could be done (though I was thinking about the same theme* a lot, during veeery looong time):
1. Make it so that the crafted items would give any special stats on any special map / gamemode (new or old) (For example, on MvM: the crafted weapons give extra cash per destroyed bot).
2. If the item has been crafted by its owner (the person who equips it), the bonus is even bigger (or it is even changed in a quality, not just in a quantity).
This way people would have choice to buy the key and open the chest OR to craft the hat / weapon to use it with the (additional) bonuses. And the metal would have more options to be used!
(Again: on special map or in the gamemode, not during the vanilla gameplay!)

(*Of course, the item_origin and/or the item_quality could be used in some user's modification, to make the gameplay more variative. "Crafted" items (even cosmetic ones) could have 1 kind of bonus, and the items "Found in crate", or "Gifted", would have another bonus, in very specific gamemode and map. On that special map, even hats would give special bonuses to their wearer.)

Source (my post in the thread "Let's talk: Keys", on SPUF)

Project 'Itemcrossing'

If you know about the existing Bookcrossing, it's clearer to see analogy.
The idea is: leave[drop?] your item anywhere on the map, so it starts it's journey through multiple backpacks.
It could have special quality (also read my post with ideas of new kinds of  Quality) "Itemcrossing". It can't be deleted, crafted, traded. It just can be in your backpack - or you can crop it too. How does it work? Well, you put your weapon - which you want to start it's journey - into Crafting window, choose "Change quality to : <<Itemcrossing>>", then you need to place it into Action Slot. Then you can drop your weapon(or any other item) on the map at any moment you want. If nobody has taken the item, it return into your backpack. After next player has taken this item, the level of the item grows up (the level is 1, at the beginning), showing how much backpacks it was inside. Also, it could have the name of the starter (the person which made this item "Itemcrossing"). So, you can use this item for your own necessities. Or you can continue Itemcrossing. NB: if you have this kind of item in your backpack, you have a week before it dissapears in your backpack and returns to the starter's backpack. Just play enough and use this item!
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Plus I had similar idea: Puzzle Fragments, that are traveling between backpacks. And you need to collect enough parts to solve Puzzle inside your backpack. But there will be special post for this idea, with details (the general part, though, is already here, in these sentences above, under the line).