Hi Dan, The go-to product for many moons has been Camger 175. It is good though that you are venting the cases. Coatings only slow down the rate of off-gassing and it doesn't prevent concentration of by products overtime. Follow directions carefully. To be effective it requires multiple coats with adequate cure time between coats. Good luck.Best, Ashley Date: Sun, 5 Mar 2017 20:30:19 -0600 From: Dan Bartlett <[log in to unmask]> Subject: Vapor Barrier Coatings Hello All: I am working with a volunteer historical society that wants to rehab some old oak store display cases into more appropriate exhibit furniture. We need a clear sealant. Is anyone familiar with an over-the-counter waterborne urethane or polyurethane or similar product that we can use as a vapor barrier? Something that's been tested for effectiveness and preferably available at my local big box home improvement store? Objects will not be in contact with the coating and the cases will be vented rather than tightly sealed. The cases are old but I'd still like to keep any residual nastiness locked in as much as possible. Thanks in advance, db T. Ashley McGrew (646) 265-5526 ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).