I experimented with three different approaches – fresh lemon juice, 2-Oxiclean, and sulfamic acid cleaner (available at most home improvement stores). I began by ensuring proper ventilation by opening a window, and donned a pair of rubber gloves to safeguard my skin. If you intend to try these methods, remember to do a patch test in an unnoticeable area first to ensure there’s no unwanted reaction with your floor material. Bear in mind that my grout is gray – thus it will never appear white. Here’s what occurred:

I scrubbed the grout lines with a slice of lemon before giving it a good scrub with a green Scotch-Brite pad. I noticed an immediate improvement in cleanliness. I then rinsed the grout lines with a damp paper towel. The only cumbersome aspect of this method was removing the leftover pulp. Once dry, the grout looked substantially better.