Marc: To answer the chemistry part of your question... Back in the days, a long time ago, when rosin flux was the primary, if not the only type of flux available, it was necessary to turn the rosin into a soap to get it to dissolve in water based cleaners. This process of producing a soap is labeled "saponification", and at its simplist, it merely means treating an appropriate oil (like rosin, or a vegetable oil) with a strong alkali, which converts it to a soap. From what I know about no-wash types fluxes (which is not a lot), I suspect that a saponifying type cleaner may be about the only type that will really clean ALL of this type of flux residues from the surface....now it could be asked what the necessity is to clean ALL the flux residues off, and wonder if a superficial, appearance cleanliness would not be adequate.....but only you can answer that. Rudy Sedlak RD Chemical Company --------------------------------------------------------------------------------- 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 To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives 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 ---------------------------------------------------------------------------------