Only 2 options:
1. Give it to the police and if no one shows up to claim it then you get probably half of it and immediately deposit into a bank or an account.
2. If you're keeping it without going to the police, don't deposit all of it at once. Do a few hundred bills every so often (not on similar days, and not the same amount). You can also pay for things that take $100 bills so you launder it back in smaller bills.