Before grafting citrus, it is important to sterilize grafting tools to both kill any pathogens that may harm grafts and also to kill diseases of citrus that are readily spread via grafting. Likewise it is important to sterilize pruning tools to avoid the spread of diseases when pruning.
Chlorine Bleach is the Best Disinfectant
Chlorine bleach is the disinfectant used by the scientists at the CCPP whose mission is to make disease-free citrus budwood available to growers. A readily available product with an adequate concentration of bleach to kill all citrus pathogens is Clorox Clean-Up. I am now using Clorox Clean-Up to disinfect my tools when grafting and pruning citrus.
Chlorine bleach can be hazardous and should be used with care. When spraying it is important to avoid exposure to the spray or mist. The material safety data sheet from Clorox recommends the use of safety glasses and recommends immediate rinsing of exposed skin with water. It can ruin clothes, so wearing old clothes would be advisable. It is also corrosive to tools; to minimize the corrosive effect on tools, it is a good idea to wash tools and then spray with WD-40 after grafting.
When spraying grafting tools, be sure to spray to the point that the bleach is dripping off of the tools as shown below. After spraying all of the tools, repeat by again spraying them all to the point that the bleach is dripping.