4. Many oils have natural purifying and cleansing properties and can be added to natural household cleaners, such as sprays, carpet deodorizers, furniture polish (lemon specifically for that one), and so on.
Try mixing your favorite aroma with baking soda for a carpet powder before vacuuming.
5. You can add oils or oil blends to household paint, craft paint or supplies, children's dough, etc to create a more pleasant aroma.
The ratio will vary depending on what you're using it for, anything from 2-3 drops for dough to a whole bottle for a gallon of paint.