I noticed you said that it drives YOU crazy, but you need to look at what the purpose of sensory seeking behavior is. He's not doing it for no reason. It's serving a purpose for him... he's trying to stimulate himself. So whatever you do to get him to stop, you have to replace the behavior with something else or you leave a void for him to fill himself.
There are many sensory toys out there. You can find them in sensory stores and there are many on Amazon too. I'm actually about to order some chewlery for my daughter. We have a lot of success with body brushing, joint compressions, chewing gum to name a few things to aid her in her daily sensory diet. She enjoys eating frozen berries, frozen french fries, and ice chips too.
She really enjoys playing in plastic bins of raw, dry rice. Before it broke she absolutely adored this sand table we had for her. One side of it held sand and the other side held water, and it came with lots of plastic "tools" to play with. It was sensory heaven for her. During the winter I filled the sand side with the raw, dry rice for easier clean up. We need to get her another one. It came with a cover and was portable too.
This is the specific one we bought: http://www.amazon.com/One-Step-Ahead-Water-Table/dp/B005E...