Some minutes ago, I saw a very impressive video making water marbles. For doing that you just need three ingredients which are vinage, calcium bicarbonat and sodium hydrogen carbonate (also known as baking soda).
So I took my iPhone and started AroundMe to call the next local drugstore. First of all I said, that I would like to buy hydrogen carbonate and she really asked me „what do you want to do with that?“. Unbelievable for such a stupid thing you can buy in any small grocery! And then after I said that I need calcium bicarbonat also, she asked me how much I want of it. Just a small amount, of course, but that’s too less – nobody would buy it and they only could order bigger amounts.