I save my pennies in one jar, my silver in another (American change, I'm sure there are similar denominations elsewhere). Pennies I find to be mostly useless to carry, so I save them until they add up.
If you do this fulltime, you might invest in a
change sorter. I haven't, but I've always wanted to
I've thought about using the pennies as projectile devices in a slingshot before. I've also heard of "people" using them to glue other people's car locks shut, but that's another story altogether.