I would totally get a kick out of Arietty taking things from Sparkle. I mean, here's a kid who gets most of his useless crap by breaking into people's homes (NPCs so far) and grabbing stuff that they won't miss. Taking it full-circle would give me so much joy.

And it'd be easy to take from Sparks, too, since he mostly just leaves things sitting around. Half-used erasers, pencils, loose change, make-up, shoelaces, whatever. Go nuts!