In canning greens, or vegetables belonging to the first group, select those which are fresh and tender. Greens that are old and inclined to be strong and tough may require longer blanching and cooking. Look the greens over carefully, rejecting all leaves that are wilted or otherwise spoiled. Cut off the roots and drop the leaves into a pan of cold water. Wash these thoroughly a number of times, using fresh water each time, in order to remove all sand and dirt that may be clinging to them. Then proceed to blanch them for 10 to 15 minutes in steam, suspending the greens over boiling water in a piece of cheesecloth, a colander, or the top of a steamer. After blanching, dip them quickly into cold water. Then pack the greens tightly into jars and add 1 teaspoonful of salt to each jarful. No water has to be added to greens, because the leaves themselves contain sufficient water. When the jars are thus packed, adjust the covers and proceed to sterilize and cook the greens according to the directions previously given. If the water bath is to be used, boil them in it for 1-1/2 to 2 hours; but if the pressure cooker is to be employed for this purpose, cook them at a 5-pound pressure for 60 minutes or at a 10-pound pressure for 40 minutes.