Works just like a tea-bag. Just boil your kettle, pop in a Quickshine bag, leave it to fizz, then rinse to leave your kettle good as new.
For tough limescale we found reboiling the kettle again with the bag in then leaving it for another 30 mins did the trick, you can repeat this a few times.
Can also be used in on shower-heads and coffee makers. Now includes instructions for Steam Irons, Espresso Machines and all Steam Appliances Safe and completely Non-Toxic
NB:- Packaging may be different from the one in the image