How long do you leave an Epsom salt poultice on?
A recommended time to leave epsom salt on is between 20 minutes to an hour. If you feel your skin burning, take it off immediately. Overall epsom salt is a pretty safe mineral to use. In some rare cases it may result in an unhealthy increase of magnesium in your body. This is only if you use it multiple times over a long period of time. Remember, everything in balance!