I am trying out Crystal vinegar in the rinse aid compartment. This is not very successful at the moment as it doesn't reduce the surface viscosity of the water, however it keeps the dishwasher fresher!
The 'Astonish' product is brilliant for removing nasty scaly deposits on the loo as well as cups thermos flasks coffee pots....
As it is just an oxygen derivative it breaks down easily, and shouldn't cause as much harm to the environment as Caustic soda products that find their way into household use.
I also used it to soak my nails in to get the tea and fag stains off my nice acrylic nails!
By the way a good tip for reducing the amount of energy you use is to put boiling water in a thermos flask. If you get one with the lever top like they use in hotels it keeps for a couple of hours.
Check out how to use a pressure cooker properly too!