Cleaning dust/dirt will probably will work fine with the Atari method Chad (I guess that Formula 409 stuff is some general household detergant stuff, I used something simular) but it doesn't do much for this residu.
You think I haven't read the book ? _I_ clipped that part and put it up somewhere here !!!

I've used Atari's method with success on the Konami GT PCB. Worked without a problem.
But that one was just filthy.
This residu is a lot tougher. I think the alcohol (thanks for that link Polaris !) will work.
(Here's a list of FAQ about that stuff:http://www.maplin.co.uk/module.aspx?ITAG=FAQ&ModuleNo=28994&doy=18m1#faq)
I'll pick up a bottle of it this afternoon at my electronics-parts dealer (
www.dil.nl , I'm a regular customer now

)
I'm still careful with the washing method. I know it works, but if there is no real need, I avoid it. However, chips on a PCB are not going to be damaged by water. You _DO_ have to remove the IC's that are not directly soldered of course. Also, I wouldn't wash PCB with lots of other components like pots etc. (F.I. monitor PCB's. IMHO the water can get in parts on those kind of circuits. The only "risky" parts on a game PCB are the one's Atari mentions and the caps maybe. And the dipswitches I guess.
So......no, I do not want to completely bath the SW PCB's prior to testing them. I _do_ want to remove the worst parts of the residu before testing however.