coffee to use in reusable k-cups.

[Gregorymorealli]

Hello.
My name is Gregory and I love dark Italian roast decaf and want to know what is the best ground or bean coffee to use in my reusable k-cups and also what is the best way to use the reusable k-cups to get the best flavor.I am trying to reuse old k-cups with filter left in cup with cap.
thanks.
Gregory.