Spray glass cleaner on the handle of the Whirlpool microwave oven. Wipe the handle clean with a soft cloth to remove loose food, grime and any other contaminants that might be on it. Let the handle air-dry before continuing.
Apply jeweler's rouge paste or polishing paste to an edge of a soft cloth. Place the edge of the cloth against the handle, to one side of the scratch. Press down on the edge as you drag the cloth along the length of the scratch to deposit the paste on the scratch. Lift the cloth off the handle when you reach the other side of the scratch.
Place the rod at the bottom of the buffing pad into the hole at the end of the power drill. Lock the pad on the drill, using the locking screw. Apply a dab of the paste to the center of the pad. Smooth the paste onto the pad with your finger. Wipe your finger off on a soft cloth before continuing.
Press the trigger to turn the drill on. Press the pad against the handle, to one side of the scratch. Press down on the pad as you drag it along the length of the scratch, using a slow circular motion as you do so. Reverse direction when you reach the other side of the scratch. Remove the pad and release the trigger after you have done this a total of six times.
Inspect the surface of the handle. If the scratch is still visible, repeat the procedure with the cloth and pad. If the scratch is no longer visible, clean the handle off with the glass cleaner in the same manner as you did earlier.
Remove the pad from the power drill. Clean the pad off with tap water and dishwashing liquid in the kitchen sink. Dry the pad with paper towels. Repeat this procedure to clean the soft cloths, foregoing the paper towels and letting the cloths air-dry.