A grass trimmer is a very useful yard tool to own. It makes trimming around fence posts, mailboxes or anything else that sticks up from the ground very easy. A grass trimmer has a hard, plastic string that is wound around a spool. The spool spins and the string cuts through grass, weeds and small sticks. Eventually the plastic string wears away and you will need to replace the entire spool. This is a very simple process.
Turn the grass trimmer upside down so you can look under the protective hooding. Clean the underside to remove stuck-on grass clippings. Use either a garden hose to spray it or a wet rag to wipe it down.
Unscrew the cap holding the spool in place. You may be able to do this by hand, or there may be a screw holding it in place. Remove the cap and the old spool from the grass trimmer.
Put a new spool in place or wind new string around the old spool. If you are winding the old spool with new string, you will need approximately 5 to 6 feet of string to fill the spool. Do not overfill, as this will cause slippage.
Put the spool back in the trimmer and screw the cap back on to hold the spool in place.