From the comments:
I’ve heard from a friend that the way Febreze works is by “gluing” the molecules causing the smell to the fabric. So you may not smell it anymore, but it is most definitely still there… doesn’t normally bother me, but it seems to bother some people heh. Assuming that what my friend told me is true, of course.
My only concern would be if the mildew stays on the clothing could it cause mildew to form more quickly next time the clothes are left damp? Probably not, but I don’t know…
Unless I’m mistaken, this sounds like a call for a visit from the Chemistry nerd!
Febreze works by utilizing molecules called cyclodextrins.
If you look at these fancy schmancy molecules you can see the centers look pretty empty. These rings are in a water solution, when these rings of varying sizes come in contact with odor molecules they trap them. The water evaporates and these molecules are left behind and can be vacuumed or brushed away.
If you like to learn about these kinds of things you would like this book: Did You Know?: A complete guide to using everyday household items. It even tells you how to make your own Febreze!
In addition to the fancy molecules Febreze also contains Zinc Chloride which neutralizes some sulfurous compounds (think rotten egg stink) and masks those scents.
Now as far as solving a mildew problem, personally I would work to rid the garment of the source of the odor.
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