To avoid rust formation, it is advisable to dry the tub thoroughly with a cloth after each use. If rust has already formed, treating the surface with baking soda or cream of tartar may be helpful.
For an even shinier result, continue the cleaning process with a vinegar and water solution. However, to remove limescale, vinegar is undoubtedly the ideal solution. Simply spray a cleaning mixture of water, vinegar and washing-up liquid into the bathtub and then pat the surface dry.
If you want to revitalize your bathtub instead, turpentine oil is the ideal natural solution.

Mix 20 grams of turpentine oil with a teaspoon of fine salt , apply evenly with a sponge, leave for a few minutes and rinse off the excess with water. After a few moments, the shine of the bathtub will be excellent without the use of harsh chemicals.
How often should the bathtub be cleaned?
In general, it is advisable to clean the bathroom weekly , paying particular attention to the sink and sanitary facilities. For the bathtub, monthly cleaning is usually sufficient, as it is frequently rinsed during use.
In homes where hard water circulates in the pipes, it is advisable to clean them more frequently to avoid the formation of limescale and soap residue. Consistent cleaning makes future cleaning a breeze and saves time and energy.
Proper cleaning can be done using the above mentioned and easily available products to which you will need to add a lot of elbow grease .
Contrary to popular belief, you don’t need to spend a fortune on special cleaning products when vinegar, baking soda or turpentine oil will do the trick. Just remember to schedule regular cleaning sessions to prevent dirt from building up and becoming too thick.