Vinegar
Everyone probably has vinegar in their house. That said, most people would probably struggle to name a dish that actually includes vinegar. The smelly liquid has a taste that is nearly as distinctive as its odor, but few people could name a food or sauce that carries that sharp sour and bitter taste. Those that could name something would likely all point to various types of salad dressings. Beyond that, the average person is at a loss. So what is the point of keeping a bottle of that smelling liquid in the house if no one eats it anyway?
Vinegar is wonderfully useful as a cleaning solution. White vinegar is excellent for descaling appliances that routinely deal with hot or boiling water such as coffee makers and tea pots. To use vinegar to descale your appliances, fill the pot or container with vinegar instead of water. Then, use the appliance as you normally would. In cases of bad scale build up, you may need to run the cycle more than once with fresh vinegar.
You can also use vinegar to descale your showerhead and faucets. Simply fill a plastic bag with white vinegar and tie it over the showerhead or faucet overnight. In the morning, remove the bag and rinse with cold water. Again, in cases of terrible scaling, you might need to soak the showerhead or faucet more than once.
White vinegar is also said to be useful for pest control. If you find yourself dealing with pests such as ants in your kitchen and do not want to spray chemicals near where you prepare food, you can scrub down the area with soap and water before following up with a vinegar rinse. The vinegar will destroy any old scent trails as well as discourage the pests from returning.