I'd replace the gaskets/o rings first, just to insure that there isn't any residual flavor that taint the beer. As part of sanitizing, put a gallon or so of bleach water in it and pressurize it, then let it all out through the tap so everything your beer will contact is sanitized. Lastly, follow that up with another gallon of clean water to gat all the bleach out! While doing this, you can adjust your pressure so you don't have to waste any beer experimenting with the pressure for a great pour. You'll love kegging, and cornys are so simple and easy to use and sanitize!