How do I troubleshoot the touch screen on an HTC Evo Shift?

My husband's HTC Evo Shift took a swim in some iced coffee and the touch screen doesn't work at all anymore. I did a full factory reset, which didn't accomplish anything. The screen doesn't respond at all. I can flip it open and use the keyboard, but that's not hardly convenient. So ... what do I try next? I'm game to experiment -- he got a new phone. I just can't accept that this one is kaput.