Tried this one today and it filled the house with a lovely smell. We had visitors and they all gave positive comments about it too. It is so easy when the wood burner is lit just to keep topping it up. The smell circulates around the house and fills the air with natural fragrance that doesn't make me sneeze!

1 pint of water
1 grapefruit sliced
1 cinamon stick broken up
4 cloves

Put all the ingredients into a pan and bring to the boil. Simmer as long as you want. Just keep an eye on the water leve and top up every so often.