Repairing liquid damaged keyboard; cleaning shorts?

I've been working on A1342 laptops for about 2 years. In this time, I've acquired approximately 200 top-case assemblies, since this part is so commonly damaged by liquid spills. I know it's extremely difficult to repair these, as it requires prying the keyboard from the case and then tediously separating the layers of the keyboard, alcohol-cleansing the printed circuits and hoping none are damaged beyond repair.

My question is, is there some "method" to repairing these? I've purchased dozens of these from a source who repairs them professionally, and they look BRAND NEW, with no indication of prying or cleaning at all. They won't let me know how they do it, but I could save literally thousands of dollars if I could figure out how to do this.

I was wondering if there was any insight into how this might be done? I'd like to avoid using a heat gun, as it warps the case FAR too easily. I don't want to completely ruin a case that could be repairable.

Any input would be greatly appreciated. My main issue is removing the internal frame from the casing. I have an adhesive that will adequately re-attach the keyboard to the casing, just no good way to remove one from the other without causing obvious pry-damage.