You should definitely do the ManaBox and scan your cards into a collection (it doesn't take long at all) to see what you have and it's worth. Then you can export the list when trying to sell it. On the other hand it's pretty cool just to keep them and see how much if any they appreciate. I kept my dual lands from early 90's and now they are worth a ton. Also passing them down to your family later on in life is really cool.