Before attempting any home remedy to remove lime scale build up, the area must be properly cleaned. In many cases, the first layer of lime scale can be removed simply by applying warm water and soap, with a little bit of elbow grease. Doing so is similar to sanding a piece of wood before finishing it---chipping away at the problem to make the next steps go more smoothly. Next, the application of acids, such as pure lemon juice or vinegar, will begin to break the lime scale down before the heavy artillery begins. White vinegar, used for centuries to clean, may be the best solution. Using a soft bristled brush (wire brushes can damage the finish of the surface being cleaned), wipe down the area in order to facilitate the next steps.
White vinegar can continue to be used to break down lime scale. For example, washcloths and paper towels soaked in vinegar may be attached by rubber band to fixtures or left to sit on the edges of bathtubs for at least an hour before scrubbing. Coffee and teapots can be filled with a mixture of vinegar and water (some suggest to boil the mixture) and allowed to sit for a day before cleaning. After rinsing, cream of tartar, a paste of baking soda and water, or borax should be used to scrub lime scales. This simple treatment can be extremely effective---even surprising---in the amount of lime being removed with minimal effort.
Finishing the Job
In certain cases, however, even these solutions will not be effective enough. Tough jobs may call for chemical solutions. CLR, a chemical designed to deal with difficult lime stain, and Lime-Away both work particularly well. Harsh household cleaners such as bleach should be used sparingly, but can work wonders on toilets and sinks. In general, cleaning products that contain oxalic acid and phosphoric acid work the best at removing lime deposits. A final trick is a product called Bar Keeper's Friend, a chemical solution that works especially well on pots and pants. By following these steps properly, most lime scale issues will recede entirely.