Dull hedge clippers will not make the clean, straight edges that make a privet hedge look well-kept. Clean cuts on the ends of privet branches prevent disease and insect damage. Bruised ends can rot or develop unsightly scars. It is not difficult to sharpen hedge clippers once you take them apart.
Sketch the position of the hinge bolt, spring and washers to help you remember the correct way to replace them. Remove the hinge bolt, spring and washers from the clippers using the correct size box wrench or ratchet. There is just enough difference between metric and standard wrench sizes that the bolt can slip if you choose the wrong one.
Clean the blades with a scouring pad and mineral spirits before sharpening, according to the advice of Australian gardening expert Don Burke of the Burke's Backyard television program and magazine.
Sharpen the edge bevel of both blades to the original angle, using a fine mill bastard file. When finished, you should feel a sharp burr on the contact side of the clipper blade, which is where the two blades meet when they are assembled.
Lay the file flat on the contact side of the blade. Scuff toward the edge until the burr is gone. The entire length of the blade should feel sharp.
Replace the spring, washers, bolt and nut in their original positions, using your sketch as a reference point.
Tighten the nut until the blades make a clean shearing sound while cutting a piece of notebook paper. The blades should return to the open position as soon as you release pressure on the handles.