Maxperson
Morkus from Orkus
On a more serious note, I'm guessing the real questions is "How can PC's hide objects". Because obviously they can be hidden, it's just a matter of determining the Perception/Investigate DC to find them.
It can be as simple as "I put it behind this seat cushion" and the DM goes "OK, that's a DC 13 Investigate."
But if you actually want to make it hard to find, then it's probably a skill check. I'd probably have it depend on how you are trying to hide it.
Hiding something by using camouflage? Survival check.
Hiding something in plain sight? Deception check.
Hiding/planting it on someone? Sleight of Hand check.
Finding a good place to hide an object? Investigate check.
Almost never an actual Stealth check. That's all about hiding yourself and being quiet.
I was actually thinking of making it a stealth(wis) check, since you are trying to figure out the best place to put the object so that someone else won't find it. The object was cunningly hidden. There are lots of ways to do it.