Hi Hlfpint40, and welcome to the forum. You must not be interested in the hobby, otherwise you would hang on to such an enormous collection? Anyway, one thing you can do is contact a local stamp club. If you go to
http://stamps.org you will gain access to the website of America's largest stamp club. On their site is a listing of all the stamp clubs in all 50 states, and Minnesota is very well represented.
One good thing about going this way is that you can trust the folks at the APS!
Peter