To preserve fresh butter, well press it and incorporate with it some salt; work out most of the water by kneading, then press into clean jars, fasten parchment paper over them, and keep in a cold cellar. Butter thus prepared will keep for several months. Fresh butter, if properly prepared and free from excess of water, will usually keep for a long time. Preservatives are sometimes added, but they are more or less harmful; borax is perhaps the least objectionable, and is added in quantities of 2 grains to 5 grains per lb.