When we are gone our 7 month old GSD chews up everything in the house. What should we do?

I have enjoyed your tapes. The question I have is my GSD just turned 7 months,and he's very playful, temperment very good. If I'm gone for a couple of hours, he will chew up or chew baseball caps, socks, papers, remotes (TV), anything, but he only does that when we are gone,and that?s not all the time, but when I come home, if he's not at the door, then he's done something. I don?t correct him hard on that, because again, he doesn?t do it all the time, but shouldn?t he be coming out of that phase? He still has a lot of puppy in him, and he is a joy. He's almost 85 pounds. I'm thinking that if he's that big, he should be coming out of that phase.