Guessing only, but a chemist's guess.

Sounds like the residue is because the flux has reacted with the soldermask,
and left a residue of solder mask behind.

Your cleaner removes the flux, but not the mask, so you leave behind mask
residue.

Any suggestion for an improvement in cleaning stands a good shot at attacking
the mask.

If this idea is correct, you have one of three choices, maybe four.

1. Change mask
2. Change flux
3. Change cleaner
4. (the easiest, and least likely to work) Get the boards from flux
application to cleaning as fast as possible.

Good luck

Rudy Sedlak
RD Chemical Company

##############################################################
TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################