Google comes through again!

Usually I have four different types of flour in my cupboard: all-purpose, self-rising, bread, and whole wheat. Since I now do little baking, the flour lasts a long time. Yesterday Ann requested a buttermilk chocolate cake for Mary Lee's birthday. No problem, except one container was unlabeled--was it the self rising I needed? Usually I keep the containers well labeled but something went awry. What could I do but go to Google about the dilemma. The suggestion was to take a teaspoon of the suspected flour and mix with a little vinegar. Bubbles should emerge from the vinegar reacting with the baking powder in self-rising. The flour WAS self-rising flour and the cake turned out great. What did I ever do without Google for my questions.