Soak freshly extracted citrus seed in water over night. Carefully cut off tough seed coat with razor blade. Place on damp paper towel in a ziploc and put it on a heat mat or router. Seeds germ pretty quickly for me this way. Many many citrus will not grow true though.
Malarky, he actually soaked it in straight water until the seed casing completely softened - more than a week - before putting it into starter soil. That was the real surprise - that it took over a month even after that point!