Have been following the various postings/answers to the problem of gold tarnish and how to get rid of it, etc. There is a better way that was developed in the early '80s. To prevent scratching of gold fingers with metal protective clips used to prevent solder pick-up during wave solder, as well as contamination from synthetic rubber finger protectors used for the same purpose, a solvent soluble organic coating was invented. The material contained a UV fluorescing dye, so it could be quickly painted onto gold surfaces, inspected under black light for coverage, then run through the soldering and cleaning processes. The temporary gold protection and flux residues were removed at the same time during defluxing. Rockwell published excellent data on this use at Nepcon West '81, paper by G. J. Engelland. Interestingly, Rockwell found the contact resistance of the gold fingers was significantly lower after this process, meaning that the yield of cards meeting the contact resistance requirements was much higher. Why? the temporary protective coating pulled out the co-deposited organics and other contaminants from the gold finger plating process. This method might be much preferred to using abrasive erasers which could leave other contaminants on the surface. I believe the coating is still commercially available, but like many other things, this "trick of the trade" has been forgotten by the present generation of soldering folks. -Bill Kenyon Global Centre for Process Change, Inc. Tel/Fax: 302-652-4272/-5701 email: [log in to unmask] ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################