Ever woke up in the morning with that incredibly bad party aftertaste in your mouth, tasting just as if a camel had slept on your tongue? And no chewing gum, no orange juice, no coffee, not even repeatedly brushing your teeth will make it go away?
Mouthwash to the rescue! It can come as a (usually alcohol-based) liquid to clean your mouth right away or as a concentrate you first have to mix with water. When gargling with it, the stuff goes farther down your throat than brushing your teeth ever will reach, and eventually it'll give you back the fresh taste you so crave.
Germany's most popular mouthwash, Odol, comes since 1893 as a concentrate in funny white glass bottles with a short, curved neck so it's easy to sprinkle a few drops into your beaker before adding the water. Its ingredients are (for "Odol ExtraFrisch"):