It is very common for teeth to yellow over time due to diet or natural aging, so please don't worry. For effective over-the-counter options, look for products containing generic whitening agents like hydrogen peroxide or carbamide peroxide. These are available as whitening strips, gels, or daily toothpastes and help break down surface stains safely. Before starting, I highly recommend a quick visit to your dentist. They can evaluate your enamel health, ensure you don't have underlying cavities that might cause sensitivity, and recommend the safest concentration for your teeth. Avoid highly abrasive charcoal or baking soda products, which can wear down your protective enamel.