When appreciating the good and bad points of skins of mink, marten, and other fur-bearing animals, every skin has its own special points, and age, season, and even sex must be taken into consideration. In a general way, the pelts of immature animals will be of little value - those from breeding females will in most cases be of no use - and every hole or tear will take off some value even from good skins. The best skins are obtained during the coldest parts of the severest winters, when the underlying fur - the soft, downy part nearest the skin-will be thickest, and the internal part of the actual skin most free from black spots and patches.