Funny you mention that, I just had the same problem on a customer's car yesterday. I used megs 205 with a terry applicator to polish the wood really lightly then put a little bit of megs 21 sealant over it to make it shine like crazy. Woodgrain is really easy to scratch especially when its the plastic wood like a GMC has, so polish gently and wipe off with a little 50/50 IPA. If you do not have megs products, you may want to use any kind of fine polish and just be gentle. Hope this helps.