Just a FYI for smiths:
1 Rusty Dagger + 1 Sharpening Stone = 1 Tarnished Dagger.
1 Tarnished Dagger + 1 Flask of Water = 1 Piece of Ore.
I will pass on more recipes if I find any on other Rusty Weapons.
By the way, Tarnished weapons dont sell for more, but they have a smaller delay between attacks.