If your grout is looking a little worse for wear and cleaning isn't helping ... DWE305 Reciprocating Saw and Dremel's High-Performance Rotary Tool, both at Amazon’ he advises.

Wrong! My grout had been stained for too long for any home remedies to have an effect. I tried some other commercial cleaners and scrubbed as hard as I could, but I was left with the same rusty ...