Dan: A couple years ago I had the same problem with a white residue. Couple things you can do. First, the particular product we were working with had to be clean, per the customer, and the nature of the product. In the past if the De-ionized water is not at the specified level, in other words been in there for a while, then that could cause it. Something to check. Second, check your rinse stages to make sure you are not getting any foaming action. The foam could cause spots or white residue. Third, call or e:mail ( [log in to unmask] <mailto:[log in to unmask]> ) Terry Munson at Contamination Studies Labs. I recommend e:mail, it's faster yet then call. In our case we had Terry come up to the plant, review our cleaning operation and we setup some tests/experiments on some boards. What we wanted to do is show the customer that what they were looking at was not a loose residue (white residue) and second that it was not harmful. We invested in CSL's ability to prove this. CSL provided us a very quick turn on the testing and information. Bottom line was we feel real good about our process and now we had the proof the process was ok. Even more important, our customer was happy that we had empirical evidence that their product was good. The reasons for step one and two is that Terry will ask you that when you call him. Hope this helps. Ron Hollandsworth ITT --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------