The most effective way to do this is by using a disinfectant such as 70% alcohol solution, bleach, or trisodium phosphate (TSP). To use alcohol, simply spray the blades of the pruning tool with the solution and then wipe them off with a paper towel or cloth. For bleach, mix one part bleach to nine parts water in a bowl and submerge the blades of your pruning shears into the mixture for at least three minutes. Lastly, for TSP, mix a 10% solution (one-part TSP to nine parts water) and let the tools sit in the solution for at least three minutes.