The color of the stain around your tub drain may give a hint as to the cause and thus to the best cleaner for the job. This page offers suggestions for cleaning stains around a bathtub drain.
The cleaner used for ceramic cooktops works very well for other cleaning jobs such as a dirty bathtub. This is a page about cooktop cleaner for bathtub stains.
Using a broom to clean your tub eliminates the bending and kneeling associated with more traditional methods. This is a page about use your broom to clean the bathtub.
This is a page about cleaning your tub with vinegar and baking soda. Instead of using expensive and sometimes harsh chemicals try this method of cleaning your bathtub.
This is a page about cleaning bathtub rings. A well used tub will often develop rings over time. If they are allowed to build up it can be quite a chore to get rid of these unsightly rings.