If you’re looking to sterilize your pruning tools, you can do better than chlorine bleach. Bleach is an oxidizing agent, which means it is corrosive. The alternative is to use an alcohol dip (ethanol or isopropyl alcohol) to disinfect your pruning tools. It can be expensive, but alcohol is readily available, and moderately safe and effective to use. Household cleaners, such as Lysol and Pine-Sol are readily available too, moderately safe, and can be extremely effective.