I am an IS2 attached to an F/A-18C squadron where the primarly role of the IS (at least on the beach) is working clearances. I would echo what several have said and that is to include anything in your past in your EPSQ. They (DSS/OPM and DONCAF) look much more favorably on a past transgression you are willing to own up to and admit the mistake than the appearance of trying to hide it. I have seen several enlisted folks kicked out for fraudulent enlistment and several officers come very close for this very thing. The example I always give is the most common infraction found by the investigators and that is drugs, specificly marijuana. If an individual "experimented" in their past, they much prefer to hear about it from the individual in question than from a high school buddy who spills the beans when they are conducting the interview portion of the SSBI (the investigation required for a TS clearance). List the past infractions and, if asked about them by the agent later, express your remorse and desire to move on with your life.