A few weeks ago, I went out to start our XJ and found the battery was dead, dead, dead. No, there wasn't even a solenoid click or any idiot lights illuminating when the key was turned on.
I had heard rumors that trickle charging these sealed gas recombinant batteries would bring them back from the dead, so decided to give it a try. I hooked up the Harley battery trickle charger and forgot about it (the XJ is driven infrequently). A week and a half later, I remembered the charging Optima and went out to check it. The Cherokee started just as it did when new! The Optima has stayed charged and works fine.
I told a friend who had a dead Optima red top battery gathering dust about this and he trickle charged his battery, too. He now has a perfectly-working red top that a week before he was going to trash.
So, if your Optima is seemingly dead, trickle charge it for a week. You'll probably end up with a working battery that's not dead at all.