What kind of textures are you using?
Dnsi or pbr?
Check to see if that area on your gloss map is black and on you metal ess is white. That would be glass shiny.
If so, then inverse the colors on that part of those maps and retest it.
Sounds like you do not want reflections on them.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit, Screen resolution 1680 x 1050.
