All you need to do it cover the bottom of a container with ice cubes and then add cold water. Take an empty pop can and put a small amount of water in it and heat it on the stove until you see steam. For us the water was boiling away for ages but we couldn't see steam and the can was turning brown so we decided to give it a try at that point anyway. We hoped it would work because we only had one empty pop can. Using tongs or an oven mitt pick up the VERY HOT can and quickly turn it upside down and submerge the top of the can in the icy water. Don't blink or you will miss it!!
Next time I'll remember to tidy the kitchen first!!