Due to the porous nature of stone, there are certain substances that can stain your sink if not properly protected. The longer a stain remains, the deeper it penetrates and becomes more permanent; therefore, it is important to remove a stain as soon as it occurs. Rustic Sinks recommend that you wipe up spills immediately and do not allow surface deposits of water bi-products such as calcium, salt, lime or detergents to build up on your stone sink. To clean your sink, use a soft cloth or sponge. Be sure to rinse the sink well after cleaning and dry. Cleaning on a regular basis will help prevent the development of hard water deposits. If you develop persistent stains, try a non-abrasive cleaner such as dishwasher soap, or a professional stone cleaner such as Stone Tech Revitalizer daily cleaner. Do not use any acidic cleaners, abrasive cleaning pads, ammonia, abrasive or soft paste cleaners, vinegar, alcohol, window cleaners or lemon juice.
If you are wanting to darken the stone color of your sink or enhance the veining, you can use a stone sealer and enhancer treatment. You can find products at many home improvement stores. Just wipe it all over with a small mount and rub any excess with a micro fiber cloth. This should last for years.