The context of the following conversation is Kendall was really into house plants and often pour water in to jars so the fluoride would evaporate out.:
Kendall says Did you know that fluoride is bad for house plants?.
The friend responds No, I usually just water them and they're fine..
Kendall responds They're not. If you don't let the fluoride out, they won't live very long..
The friend responds You might be right, my plants die a lot..
Kendall responds If you pour the water into jars and let them sit, the fluoride will evaporate and the water will be OK to use..
The friend responds Wow, I'll give that a try..