I have one of those little crock pot looking things that sits on my counter. You are supposed to put potpourri in it with a little water and plug it in for a wonderful scent. That is how it is supposed to work. I have not been using it because potpourri is either attractive enough that I want to put it in a container where it can be both seen and smelled or it looses it's quality quickly and must be disposed of after being used in the little pot.
Inspiration! I use small pieces of leftover fruit, like apples, or oranges in my little pot. I have been experimenting but have found I can use apples, orange and lemon zest and rinds, along with a smidge of cinnamon, nutmeg, and cloves. Nothing harmful to breathe there. I can use fruit that is past prime eating or leftover from a child who did not finish it (upcycling at it's finest!!). Because the pot is tiny I am only using a little and even the peels will do.
Also on my list are thyme and lavender. I can't wait until summer!