The mirror fulfills its purpose only when it is clean. Unfortunately, this is exactly the problem, as many manufacturers do not include mirror cleaners in their mirror care instructions. The main reason is corrosion at the edges of the mirror at the bottom. This happens because the cleaning liquid falls on the silver coating as it runs down and affects it from below. This can be avoided by using special cleaners for mirrors, not for glass, but specifically for mirrors. Always choose mirror cleaners carefully, don't look for a low price to keep the mirror coating intact.