Headlight Restoration on the cheap.
Step 1 - Wash the headlamps with common dish soap and allow to dry thoroughly, this will remove the dirt and oils from the lamp.
Step 2 - Using regular rubbing compound or silver polish (I used Silvo brand silver polish (about $4.00 a can here in Canada), it may work with copper polish as well) Apply a small amount of compound or polish using a soft cotton cloth (an old t-shirt or sheet cut into manageable size) gently rub the lamp in a circular motion (the amount of pressure is determined by the severity of the dullness, you may need to repeat the procedure more than once) allow the polish or rubbing compound to dry to a haze, usually by the time your done both lamps the first one will be ready to perform the next step.
Step 3 - Using a clean dry cotton cloth buff the lens to remove all of the haze, if the lamp still looks dull repeat step 2.
Step 4 - Once you are satisfied that the lenses are as polished as they will get, wax both lamps with a high quality auto wax, (a wax containing carnuba is the best) Mother's or Maguires works great. The wax will prevent bugs, dust and dirt from sticking to the lamp and it will retain it's clarity for a long time, if the lamp starts to look dull simply apply a new coat of wax.
Step 5 - Stand back and admire your newly restored headlamps - you will be amazed at how much further you can see at night.
*The attached photo is of my headlamp on my 1998 Suzuki Esteem - The before picture is from another 1998 Suzuki Esteem, my lamps were almost as bad as the one pictured here.