I encountered the same thing with Russell fittings, tried cleaning them off all to no avail. I'd bought them from Summit and sent them back at no charge for shipping, both ways, to me after talking with a "tech" and customer service. Worth a try!
I ended up using Earl's fittings on everything for the fuel system. I'd ordered a couple of Summit fittings but their anodizing is a different color than Earl's...sent them back also(yeah a bit anal, I know ). FWIW.