_Wearing Quality of Paper._ Many times a typewriter will have a rubber roll (platen) which has become pitted and worn from age and the use of periods, commas, hyphens, and ditto marks. This is very destructive to carbon paper. New rubber rolls should be placed on the machine. It is not economy to use the cheap variety which can be purchased for 75 cents and which is nothing more than rubber hose drawn over a wooden core. The latter is not cylindrical and will give trouble. The type will print unevenly and cause bad alignment, for which the machine will be blamed. =Blinds.= _Blind_ is the name given to a sheet of paper used in connection with manifold work for preventing all of the information on the top sheets from being manifolded on certain of the sheets underneath. For instance, in describing the scheme for providing the packing department with a description of the goods to be shipped, but with the quantity column blank, it will be remembered how a strip of paper of proper size wide enough to cover the quantity column was placed over the left side of the invoice from top to bottom. Therefore all quantities, instead of manifolding onto the packer's sheet, manifolded onto the strip of paper known as the _blind_. A blind may be of any given shape, and cut away at the top, side, or bottom; or, in some cases, irregular-shaped cuts are made in the middle of the sheet or near the edges. The cuts are made in order to allow certain information to be manifolded on the next sheet under the blind. The balance of the information on the top sheet is manifolded onto the blind, which is thrown away. It is reasoned that it is cheaper to use a sheet of paper for this purpose than it is to stop and make a separate sheet with part of the information only, typewritten thereon. HOW TO HANDLE ORDERS AND BILLS ON BILLING MACHINES