After primary fermentation settles out, if you are still worried about the sheen, you can try racking to a secondary. If you do it gently with a siphon and sacrifice and inch or so of volume, you should be able to leave the sheen behind. It is likely from a very thin coating of oil or similar organic substance to protect the copper from corrosion / verdigris formation during storage.
Secondary: Fool's Errand II
Bottled: Red Pepper Export Ale, Beach Ball Blonde