The armrest in my car is often full of coppers.
The great thing is TESCO self service machines accept 1p and 2p coins so I save them up and buy donuts when at work without a care in the world for how long the next man will have to wait for me to finish inputting 50-100 copper coins.
Donuts, serious business.
I use a couple of Pringles tubes as they're pretty sturdy and have lids to them, it's just a whole lot easier than carrying the change about plus once every few months I've got enough cash to treat myself to a couple of DVDs or whatever. If I didn't chuck spare coins into there I'd only end up wasting it on something useless.
20p pieces are okay value to weight ratio, I 'save' 1, 2, 5 and 10 pence coins. Carrier bag in a box... however after around three years the bag's full and no chance it can be moved in the bag, it must weigh over 5kg.I don't carry anything less than 50p pieces on me, so aye, I have a huge pot full of change.