My cleaning project is to try to make like new a shower base that has turning beige. Is there a cleaning solution that will make it like new. Someone at Home Depot told me to get a fiberglass cleaner for boat hulls. Other say try the fiberglass cleaners for cars like Corvette which are fiberglass.

Secondly, what can one use to clean the white grout lines that have also turn beige. Would a toothbrush be the right tool?

What would you use to apply the cleaning solution?

Any suggestions would be welcome.