Ask this question on the Conservation Distribution List. I have never used it, opting for the straight methyl cellulose polymer. However, many have used it and they will be on the Cons DistList. See below. If you can't get on, I'll submit the question for you. Tim Vitale Preservation Associates 831-684-2731 Administrivia for Cons DistList: Mail submissions to [log in to unmask] Administrative matters (file requests, subscription requests, etc) to [log in to unmask] DistList Archives: All instances of the DistList are available (both for browsing by whole items and searching for individual messages): http://palimpsest.stanford.edu/ The ConsDir is available at the same site.