Hi Max and B_S,
I guess the the drilling idea wasn't the sharpest thing I've come up with. Maybe using a very sharp smaller size nail and laying a rag over the whole area while laying the can in an open vice so it's contained and supported. Then just swiftly drive the nail in just enough to pierce the can and allow the pressure out. Make sure you have plenty of rag on hand so that any expelled paint doesn't make a mess of everything around you.
After that one must enlarge the hole that's been made in the lower section of the can so as to drain the remainder out and put it into an airtight container.
B_S,
as far as shaking them for around 10 minutes is concerned just take a can with you where ever you go around the house and continually shake it when your hand is free. You'll be surprised how quick 10 minutes goes past.
I'm about to put a photo up of the handle bar assembly fully polished in raw steel.
Cheers,
BB.