How can I encourage my Grey to bathe?

I have tried everything. Misting him with spray bottles is totally unacceptable. He tips any bowls (or heavy crocks) that I put in his cage- he thinks that is entertaining. He prefers to bathe in a three inch wide X one inch deep bowl on his playstand- which he barely gets wet in. Showers are a no-go too, even if he's with me. Anyone have a solution to this problem or should I just let him bathe in that tiny bowl?