Hi Paul, The I've seen tarnishing of this type twice before , in both cases it was due to the washing process. 1. Water not being completely wiped from the component bodies by the turbine blowers prior to IR drying - This burnt the water off the body leaving the discoloured finish on the metal surface. 2. The other occasion, which I don't think applies to your crystals, was a reaction between an anodized metal surface and saponifiers in the wash. If you manually dry the boards by intervening between the blower & IR sections it should confirm or rule out my suspicions. Hope it helps. Neil Roche. Paul Wareham <[log in to unmask]> on 22/01/99 01:50:51 Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to Paul Wareham <[log in to unmask]> To: [log in to unmask] cc: (bcc: Neil Roche/DOV/DIIG) Subject: [TN] Tarnished marks on crystals We are using a Fox type HC49U crystal on one of our boards and after wave solder and washing, the body the crystal seems to be tarnished or discolored with a yellowish tint. It does not appear to be a residue and the rest of the board is clean. Any idea what could caue this kind of stain anyone? Paul Wareham DynaGen Systems Inc.