Common etchers of stone include: Any acid-based food or sauce, such as citrus and tomato, Red Wine, Mustard, and Oils such as butter, margarine and cooking oils. These should not remain on a natural stone surface for any length of time, even if that surface is sealed. Stones should be wiped clean with a warm, dampened cloth immediately when contact with any of these substances is made. If a natural stone surface has been accidentally damaged and/ or stained there are stone restorers that may be able to remedy a problem.