I've been fascinated to read this discussion as I have recently cleared my skin after a month gluten and dairy free. NYGuy, I would recommend two or three weeks completely free, that will give you a good indication of whether or not gluten is a problem for you. Sometimes I find just small amounts make a difference for me. I would also recommend not letting yourself get too hungry. If I let this happen I am almost irresistably temped to grab something quick that will hurt me - a scone, a slice of pizza, something like that.
Years ago i also cleared my skin with a very restricted diet similar to what other people have written about - no wheat, dairy, yeast, sugar, nightshade vegetables, corn, nuts, deep friend food, citrus, a very long list. Unlike this diet, gluten and dairy is something I can manage for easily for the rest of my life, and I can tell there are a few things I am still eating that are slightly problematic. At this point I can remove them and see what the difference is.