While bleach is a damn good disinfectant (it kills literally EVERYTHING), its not the best thing to clean a rig, contrary to popular belief, because bleach is exteremely poisonous, and even 1 part per million IV can have really nasty effects if it doesn't kill you. The best word of advice, of course, is to use a rig once and dispose of it. If thats not possible, the best way to clean a rig is to draw water into it to the maximum capacity, and then to boil the whole thing in a pan of water like this for 5 min. starting the time only AFTER the water comes to a complete boil. This will render as close to sterile as you can get without an autoclave. (autoclaves use high pressure hot steam at a temp of 200-300 degrees F for 30-60 minutes, which are how rigs are sterilezed at the factory.) The next best way would be to obtain a small amount of betadine (also called povidone-iodine, which you can get in drug stores), which is an iodine-based solution. This is the stuff they use to prep skin prior to surgery. dilute the betadine in water to the point of light brown. Fill the rig with the solution to maximum capacity, and let sit for two to three minutes, making sure the solution is in the needle itself, as well. Then rise the for ten miniutes in clean running water. This means drawing back completely with water and then flushing it out repeatedly for 10 minutes straight.This wont do as well as boiling and its a real pain to get it all out of the syringe, but still safer than bleach, because its color is a dead give away.