If you're not sure where to start, then perhaps you should try using soap and warm water first. It's cheap and easy to make but can leave streaks behind.
SOAP AND WATER
However, if you're looking to remove stubborn stains from your mirror, then this could work well as a starting point.
SOAP AND WATER
Simply wet a cloth or sponge and wipe down your mirror. Make sure to avoid getting any water into the frame itself.
SOAP AND WATER
You may need to use some sort of tape or masking material to keep the frame safe during the cleaning process.
SOAP AND WATER
If you'd like to keep things simple, you could even buy a bottle of liquid hand soap and use that instead.
SOAP AND WATER
Just remember to rinse off the soap before drying your mirror.
SOAP AND WATER
Remember, different solutions are required for each different type of cleaning, so avoid tipping alcohol all over your mirror for example, as this is best used for spot cleaning.