On the stove boil a small pot of water with a few cinnamon sticks, a few cloves, and a few(or as many as you want) orange slices. Once it boils turn it down and leave on low and turn it off when ever you want. Just make sure you watch the water level. You'll have to keep adding more as it evaporates. You'll always get a reaction when anyone comes in your home. It smells so good!
I don't know how long you can keep it before it goes bad. I just give it a few days. You'll notice when it's been warmed enough and the contents don't look appealing anymore. Maybe Mary Coleman or someone else out there who does this can comment with an appropriate length of time.
If you do this and add other spices and flavors let us know!
11 month pictures to come... I have to take them first. Didn't realize till 5:30 this morning that I missed the actual 11 month day!