My preferred method is to march them at the head of a large army against an equally large enemy army. You do not automate it at this point. This almost never kills your general off on a first go. With the battle underway on the battle map, march your forces right up to the enemy line, close enough so that they start feeling threatened and are shooting/throwing missiles while yours do the same. Then, use ONLY your general's unit to charge at the center of the enemy line. Your general's bodyguard unit, with its great morale, will usually never rout if it's so close to all of your other units, even though your other units are ordered to hold still and aren't really engaging the enemy. The AI will focus much of its energy on your general's unit, and it doesn't take long to whittle it away, eventually killing the general himself. Viola! You can then fight the rest of the battle if you want to, or simply tactically retreat if you want to preserve your forces without a real fight.
You could do all that, or you could call my cousin Vinny. Yeah, he's a real wise guy. Knows how to take care of problems and pricks that make your life a miserable
ing hell. Yeah, he'll do it nice and quiet too, put that mother
er's brain to sleep.