The best thing to clean a mattress with will depend on the type of stains, dirt, and odors present on the mattress, as well as your personal preferences and any allergies or sensitivities you may have. Here are some of the most effective and safe cleaning solutions for cleaning a mattress:

1. Vacuum: A good quality vacuum cleaner is the best tool to remove dust, dirt, and debris from a mattress. Use the upholstery attachment to vacuum the surface of the mattress thoroughly. This will remove any surface dirt and debris that may have accumulated on the mattress.
2. Baking Soda: Baking soda is a natural and effective cleaner that can help to remove odors from a mattress. Simply sprinkle a generous amount of baking soda over the entire mattress, let it sit for several hours, and then vacuum it up. The baking soda will absorb any odors and leave your mattress smelling fresh.
3. Enzyme Cleaners: Enzyme cleaners are a safe and effective solution for removing organic stains, such as blood, urine, and sweat, from a mattress. These cleaners contain natural enzymes that break down organic matter, leaving your mattress clean and fresh.
4. Hydrogen Peroxide: Hydrogen peroxide is a safe and effective solution for removing stains from a mattress. Mix equal parts of hydrogen peroxide and water in a spray bottle and spray the solution onto the stain. Let it sit for several minutes, and then blot the area with a clean cloth.
5. Steam Cleaning: Steam cleaning is a popular method of deep cleaning a mattress. This involves using a steam cleaner to remove dirt, dust mites, and other allergens from the mattress. Steam cleaning is effective, safe, and environmentally friendly, making it a popular choice for many homeowners.