I find it is very effective to say, "I'm a practicing Catholic, let me tell you about my church!'"  Most of these proselytyzing types are the sort that think that Catholics worship statues and are going straight to hell.  They shut up and go away pretty quick, afraid of catching Catholic cooties. I welcome one and all to use this approach; Catholic or not. Now; all of this was advanced education in marketing and logistics.  Not to mention the artistic talent needed to put labels on box