In article ,
says...

On Sun, 1 May 2011 17:16:35 -0700, George W Frost wrote
(in article . com):



One of the many jobs I have had, was in a machine shop making screws and
bolts
the problem with the ones you have may be in the final washing where the
screws are washed in a solution, to get rid of any residue
I can't foresee any problems with an oily residue on the screws to inhibit
their performance


I agree that for the mechanical fastening of the drywall panels to the
framing the oil does not inhibit their performance in any way. If however
you include user friendliness as part of a product's performance then the oil
is a pretty serious flaw. Also in drywall work it is very important that the
mud adhere tightly to the screw heads so could also be another flaw there.
Thanks.

Personally I think I'd want to find out whether the oil is normal or
not. Have you thought about sending a box of oily screws to the
manufacturer and asking if the oil on them was normal? If it isn't then
it's getting on them in transit somewhere and I suspect they'd be happy
to help you find out where and apply some pressure from above to get the
problem addressed.