Help with Porcelain Tile clean up problem
Our contractor installed porcelain tile and sealed the grout. After a major clean up we noticed some grout residue and used a diluted vinegar/water mix to scrub it off. But in doing this we are left with small circles from our scrubbing which are duller than the rest of the tile. Have washed many times but the dullness is not changing. How do I fix this?