want your bathtub back to that original bright white?
use tilex sOaP SCUM remover! it's the BEST ever! i will never EVER go back to comet. i cleaned my bathroom from bottom to top, sides to sides, crevices in crevices last weekend with tilex (even on shower glass doors!) and windex. the pay off is: my bathtub is still bright WHITE! o YeaaaH! make sure you have good ventilation or you'll be on the verge of passing out.

yes, i'm a dork and a bit anal when it comes to cleaning. :P