Remove the spool from the trimmer head by pulling firmly up on the tap button. The spool and tap button are a single unit.
Cut two 12-1/2-inch pieces of 0.080-inch monofilament Weed Eater string, using a utility knife.
Place the tip of one string at least 1/2 an inch into the small hole in the side of the spool. Wrap the string around the spool until you have 5 inches left unwound. Press the string into the retaining clip on the edge of the spool to hold it in place.
Place the tip of the second string at least 1/2 an inch into the second small hole in the side of the spool. Wrap the string around the spool until you have 5 inches left unwound. Press the string into the retaining clip on the edge of the spool to hold it in place.
Attach the spool to the trimmer head and snap it into place to secure it. Pull hard on each string to release it from the retaining clip.