For whiter tile and grout, you can stop looking to commercial cleaning products. All you need is right there in your kitchen—cream of tartar and a lemon or lime.
Sprinkle cream of tartar on the tile and grout, then scrub with a cut lemon or a rag that you have saturated with lemon juice. On a vertical surface make a paste of cream of tartar and lemon or lime juice. I found that a bottle of lemon juice was tidier and easier to use.
I spent a year trying to turn our gray bathroom tile floor and grout back to white, to no avail, until I tried this tip. It worked like magic! Team EC