I found this in "Green Witchcraft" by Ann Moura. I've used this & it worked.
On a piece of paper, write down the name Benedida*.
Crease it, wave it through the air and snap it closed.
Fold the paper up, saying, "Benedida, I have you here & I will not let you go until you return the missing ________."
Hold the folded paper tightly and place under a leg of a heavy chair (you don't want Benedida to escape).
Go back to looking for what you lost...it will be found.
Thank Benedida for returning your item and unfold the paper & bury it.
*Benedida is the Thracian Moon Goddess