This is how we do it at my facility.
First, whenever possible, if buying new tools, I try to get two sets. One we have for regular reg service, and the other that gets O2 cleaned and then is only used when doing O2 service. To clean, first, we degrease/wipe down the parts with a lint free rag soaked in isopropyl alcohol. This removes any gross contaminates. Then we immerse the tools in a hot mixture of 2 capfuls of Crystal Green or Simple green in hot distilled h20 in the Ultrasonic cleaner. I prefer to use crystal green, but it is not always in stock at grainger. After washing, they go in a second ultra sonic cleaner for a rinse bath of distilled water. Due to a couple deals I have worked out with an analytical lab, I can run a sample of the rinse down to them and have them run it through their mass spectrometer to make sure I got all of the hydrocarbons off of it. Usually talks less then two hours including the drive. They do this for me for free because they use the tests as a training opportunity for their lab personnel. Finally, we blow dry the tools with compressed nitrogen, and then check with a UV light. (if contaminates are found, we go back to step 1 and restart.) Depending on how soon we plan to use them, we will store in a O2 cleaned container, or vacuum pack the tools to prevent contamination.
While this would seem like overkill to most, I occasionally do O2 cleaning and work on pure O2 systems outside of the recreational diving industry. The customer insists on these procedures, and happily pays the added cost. Of course they also insisted we build a semi permanent clean room that is over pressurized and uses HEPA particulate filters, and we wear tyvek coveralls when working on O2 equipment. Because it is already set up this way, I can utilize the same tools and equipment for O2 cleaning of regs, tanks, and valves for no additional cost to the diver.
