Make sure the light has an epa approval number as proof that it will really do the job, one point is to be sure it is rated to kill the bacteria and the spores… strong UV will kill bacteria, spores are a tougher nut to crack although in theory enough uva-a will kill anything…… But then strong UVA will do bad things to some gemstones….
It sounds funny to refer to an epa rating , you would think that the FDA would be the ones to certify stuff, but the way they divvy things up it falls to the epa’s turf to certify disinfecting and sterilizing methods and products, while the FDA sets the types of test to certify, based on input from cdc, industry and the medical field. Up here in canuk land we have health and welfare doing the fda part with agriculture Canada doing the epa part for certification
Also light can only work where it is able to reach, some spores for example behind a stone would not be killed.
Again no matter what method is used, the method must be followed to the letter. For example Ron mentioned steam… yes steam will do the job but not a little squirt from a jewelers cleaner, we would be taking hospital level Sterilization which is in an autoclave at 270degrees f at 15psi pressure for 3 to 15 minutes once a stable temperature is reached depending on the degree of sterilization wanted