Over the years, I’ve stocked up on my favorite 0.5 mm gel pens, colorful cotton ... to try to clean the once bright-white grout lines between my subway tiles with any sort of efficiency ...

For use inside or out on a variety of surfaces including sanded grout, ceramic tile, porcelain tile, glazed tile, stucco, travertine, marble, slate, granite, terrazzo and more to protect against ...

Additionally, the pen was not an exact match for our backsplash or tile floor grout. After using it, the area we "cleaned" no longer appeared dirty, but it didn't match the surrounding grout lines ...