Watching Greece riots and tear gas canisters, I think I have a solution...

make an air tight container that is a cylinder that is split down the center with a hinge on one side, allowing it to operate like a clam shell.

• Locate tear gas canister cops have shot into protest group.

• Place inside cylinder

• when closed locks from the inside.

• Throw at the cops. This will expand quickly inside and create a bomb that will explode and cause shrapnel.

I think this will make cops think twice about using tear gas.