For the nails, you can use a magnet. You can separate the marbles and corks by putting it in water, wood floats and marbles don't.
You will invariably lose or ruin a certain number of corks. It should be less than five percent however. Since corks won't be overly expensive you should just add a few extra to your order. That's a matter of choice, but corks aren't expensive and you would eventually need more corks any way. So if you order some extra corks it's not going to be all that expensive.
Actually, you can get some corks on Ebay. They have a decent amount of wine-making supplies.
When they found out he used corks in his bat not shure if I spelled corks right but it is illegal to put that in your bat.
red and white
Spool
using a screen
the cork floats because it is has density
Wine, port, corks.
to not make it rot
you shouldn't do that
it is the inner bark of the cork oak tree.