Rinse the shears in soapy water, removing any dirt on the blades. Use a wire brush to scrub away stubborn dirt.
Wipe the blades with a rag soaked in turpentine to dissolve any dried sap on the shears. Turpentine also removes paint, so keep it away from painted wood handles, when applicable. Rinse the shears in clear water.
Combine 1 part household bleach with 9 parts water. Submerge the shears in the bleach solution.
Soak the shears in the bleach solution for 30 minutes to completely sterilize them.
Remove the shears from the bleach solution and rinse them in clear water. Allow the shears to air-dry before use or storage.