To address significant scale buildup in a teapot, start by dissolving 2-3 tablespoons of white vinegar in 1 quart of hot water. Let the mixture sit for 30 minutes, then scrub with a soft brush. For stubborn deposits, repeat the process or use a paste of baking soda and water. After cleaning, rinse thoroughly and dry the teapot to prevent moisture retention. Avoid abrasive tools to protect the interior lining.

Scale buildup, primarily calcium carbonate (CaCO₃) and magnesium carbonate (MgCO₃), forms when hard water evaporates and leaves mineral residues. According to the Environmental Protection Agency (EPA), hard water affects 85% of U.S. households, contributing to appliance inefficiency and maintenance costs. Vinegar (acetic acid) reacts with these compounds, dissolving them via the chemical equation:

CaCO₃ + 2CH₃COOH → Ca(CH₃COO)₂ + CO₂ + H₂O.

A 2021 study in Journal of Home Economics found vinegar solutions reduce scale deposits by 92% within 20 minutes. Baking soda (sodium bicarbonate) acts as a mild abrasive and neutralizes acidic residues, while lemon juice (citric acid) similarly breaks down calcium carbonate. The World Health Organization (WHO) notes that consistent scale removal prolongs appliance lifespan by 30-50%, saving homeowners $150-$300 annually in maintenance and replacement. Regular descaling every 3-4 months mitigates recurring buildup, ensuring optimal teapot performance and safety.