Quick answerA stain is liquid that has soaked into the pores of the stone, so you draw it back out with a poultice, a paste left on the mark for 24 to 48 hours, repeated until it lifts. A sealer only slows how fast liquids soak in and wears off over time, while DURAFLEX surface protection film stops staining outright, which is why complete protection means sealing the stone to prepare it, then protecting it with DURAFLEX.
Marble is beautiful and fragile, and the first thing worth knowing is that a stain is not the same as an etch. A stain is something that has absorbed into the porous stone: cooking oil, red wine, coffee, tea, or rust from a tin left on the bench. It usually shows up as a darker patch. An etch is different, it is a dull or lighter mark where an acid like lemon, vinegar or wine has eaten into the polished surface. This guide is about lifting genuine stains. If your mark is a dull spot rather than a dark one, that is etching, and the fix is different.
The good news: most stains can be drawn back out of the stone, because the same pores that let the liquid in will let it out again with the right method. The honest news comes at the end: once you have cleaned it up, the only way to keep it from happening again is to stop liquids reaching the stone in the first place.