why not carefully cut out the fuzzy portions of the poster paper just back to good smooth sections.Then carefully apply a patch of the same type poster paper to the back of your poster.Use white glue and make sure that your patch is has enough glue to glue down all edges.put wax paper down then lay your poster facedown on waxpaper.Then lay some waxpaper on top, over your patch,and weigh down with a bigbook till dry.Carefully reblend color where your patch is?

duct tape