Skim fat off the surface of the stock with a perforated spoon. When as much as possible has been taken off, dip the end of a clean cloth into boiling water and wipe the stock with it until stock is free from grease. If the stock has not jellied, use a paper towel instead of a cloth to remove the fat.
It is best not to remove fat from stock or soup until it is about to be used as it keeps out the air and helps to preserve it.