I would be mesmerised for hours if someone provided me with a glass jar and some weird bug inside it crawling about
I hate bugs but when you know they can't get you, they're awesome to watch!
keeping and/or removing jam in/from
You coukd use jars for storage of stationary like i do. But its neither fun nor creative.
Maybe you could use it to hide things from peolple, decor in your room, um not sure what else really.
Cant be much help here.
I'd fill it up with really pretty sweets never to be eaten but to sit on the book shelf and look pretty and taunt my stomach.
I like to drink water out of them. Sometimes.