Rich, Check this out. http://cool.conservation-us.org/coolaic/sg/bpg/pcc/10_spot-tests.pdf Section 10, Page 24 Spot Tests. The reference at this point is Barrow 1969, 13, TAPPI T408. I did not follow this up. I have never used the test myself. Bev -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski Sent: Wednesday, May 23, 2012 6:28 PM To: [log in to unmask] Subject: [TN] Spot test for Rosin Residue I seem to recall a wet chemical spot test for rosin residues. Something that required: * Piece of filter paper. * Sugar solution . * Dilute Sulfuric acid. If the final spot went red, it would indicate the presence of rosin. Does anybody recall this test and have the details? Thanks in advance Rich Kraszewski Plexus Engineering Solutions ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________