Gardening tools should always be cleaned after use, but this doesn't always happen if the last person to use them was in a hurry, not educated about tool cleaning, or the tools have never been cleaned. Cleaning gardening tools requires only a couple of minutes of your time and can be of great benefit if you do so before using.
Use a high-pressure setting on your garden water hose to wash off any caked-on dirt or debris from the gardening tools. Angle the tools so the water hits all sides and gets as much dirt off as possible.
Use a stiff brush to scrub off any bits of debris or dirt that the water didn't wash away. Scrub the tools until they are clean.
Soak an old rag in paint thinner, and then rub it over any gardening tools that have sticky debris, such as sap, plant membranes, and glue.
Soak a separate rag in oil (such as WD40), and rub it all over any metal tools. This prevents rust, helps lubricate the tools, and causes them to work at full potential. Wipe them dry with a second clean cloth. This should be done on all supplies that contain metal, such as shovels, rakes, shears, pruners, and trowels.
Sanitize all of your pruning tools or tools with blades with rubbing alcohol prior to use. This helps ensure that no harmful bacteria will be spread to the plants when they are being trimmed.