I read through some archives on OSP boards but didn't find as much as I think I may need. We have OSP boards that are run through topside reflow, bottomside reflow, wave solder processes. These processes use water based pastes/fluxes. (Which I gather may be the cause of the residue?) The residue we see is not very prominent - seems to "outline" or shadow the circuitry if you will. What are other experiences with OSP finishes and white residues? Do you let go as is? The residue is permanent and does not come off with Proclean or aqueous wash. Jan Pelchat --------------------------------------------------------------------------------- TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF TECHNET Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------