I should have known that something like this had been invented and I probably should have blogged about it before this.
Growler get gunky. I have seen horrified faces at breweries when a dirty growler has been brought in for more beer. I have heard tales of some growlers so bad that they were immediately put into the recycle bin.
Now those people, and me, can simply drop Growler Tablets from Craft Meister in a tablet add water and let sit for a nice clean piece of glass.