I need help... From A Stamp Expert.

I just had passed in my direction a HUGE suitcase full of stamps,and a couple of stamp books,there are over 500,000 in quantity. These are not all new stamps, most are used and were once hinged. I am not interested in getting the guides and looking at each stamp,because that will take FOREVER.
I would like to know if its better to sell stamps in lots by country or sell them randomly for like 5 cents each?
Also, which ones to look out for that may be worth something?
Thanks,
Angelique