When you clean your diffuser out, you must empty the tank. It may seem like a waste dumping out that water and oil. However, because it’s been sitting there for a while, it’s best not to reuse it.
However, if it’s only been in the tank for about one day, you can pour it into a spray bottle. Add some more water and even some white vinegar. Use it as a room spray or as a multi-purpose cleaner.
It will last for weeks in this bottle since it is airtight.