I’ll confess something: for years, I dreaded the grout lines in my kitchen floor. No matter how much I mopped, that dingy, gray shadow lingered between the tiles, making the whole floor look perpetually dull. I’d tried every bottle from the store aisle—promises of “brightening!” and “whitening!”—but they either left a filmy residue or just moved the dirt around. I was about to call a professional regrouting service when my grandmother, a woman who kept a farmhouse spotless with the most basic supplies, shared her timeless formula.
