Supplemental comes from the title and description tags. Make every pages have a unique title and description meta tag and you will come out of Supplemental. This is how google determines if it is unique or a supplement page.
this might help you, about matt cutts suplemental results http://video.google.com/videoplay?docid=-3494613828170903728&q=matt+cutts+%2B+supplemental+result&hl=en
Thanks. Not sure that answers my question though. I have never had supplemental web pages and now almost all of the are. Can this be a mistake?
My site has gone this way to.. Unique titles and descriptions from the start.. 95% indexed as supps Have tried everything to get out unfortunetly no luck so far.