If it can have wax poured into it, fragrant or essential oils in the wax, Wendy can pour into it (and often does).
This is why they are special, limited availability
It’s just an object with wax poured into it so it smells nice.
If there is room to add a wick you have a fragrant soy wax candle.
Soy Melts that are used in oil burners. Replacing the often dangerous hot burning oil, Soy Wax has a low melting temperature so if an accident happens and the wax gets spilled it is easy to clean up.