1. If people knew i found it, I'd contact a lawyer and try to be in the best scenario where if the police couldn't find its rightful owner that I'd get it. If nobody knew then proceed to #2.
2. I'd keep me ears open if anybody was missing that amount of money. I'd consider running anonymous craigslist ads (have to be careful to be truly anonymous). If i didn't find the rightful owner, or if the rightful owner was determined by me to be bad people i'd proceed to #3.
3. I'd buy gold and silver but in smaller then $10,000 increments so that it wasn't reported. This way the money stays under the radar and keeps me safe from bad men, but also increases with inflation.
4. I wouldn't do anything with this gold or silver for 10+ years, maybe even 20+ years. Then I'd start selling off gradually selling off, and maybe giving some gold/silver to close relatives.

Any advice on how to do this differently or better?