Over 800 dishwasher cycles later and the keyboard still functions as if it were brand-new. All I need to do is replace the PS/2 cord which has worn out at the strain relief.
Reading your comment, I thought either "nobody is going to believe this guy" or "people are going to think he's nuts". Actually, I thought it sooner than that, because I almost shared a story about how I used to clean up my Northgate Omnikey and decided not to because I didn't want to be judged. :) And yet, here you are, with an equally insane, similar but much better approach.
My method for cleaning my Omnikey was to fill the kitchen sink with water and clean it like one cleans a dish. After a quick towel-dry, I'd toss it in the oven for 12-or-so hours at the lowest temperature (I think about 150-200 degrees American). I did this at least 10 times during the decade and a half that I used this board (and it was sold in perfect, working condition).
I'm sure I did some damage, somewhere. There's got to be parts in that keyboard that corrode, but it always came out "like new". I haven't owned a keyboard like it since and I expect the one I use day-to-day wouldn't survive a strong gust of wind. I'm not completely, nuts, though. The first time I performed this all-day, insane, cleaning routine was after I had lost all hope of resurrecting my keyboard due to an unfortunate encounter with a full glass of Mountain Dew.
At no point did I ever consider putting it in the dish washer. That would have saved me hours!
Sent my Apple Pro keyboard through my dishwasher last week! Hadn’t been cleaned in probably 8 years so in addition to looking almost brand new, it now types significantly better.
When I worked for a CS department long ago, I took all the Sun Type 4 keyboards home in batches of 6 to run through my dishwasher.
I would never do it to a board unless I was really sure it was completely unpowered when disconnected, and waited days for it to dry.
There are lots of other caveats depending on the exact keyboard and exact dishwasher model.
I wouldn't dream of using my current dishwasher. The heating element cannot be turned off and it outright melts some less expensive (barely dishwasher safe) plastic-ware.
Probably good for cooking crab legs, but would likely warp the plastic on a typical keyboard.
I've put model M keycaps and the top shell (no decals there) in the dishwasher. Keycaps came out great. The shell warped slightly from the heat but it was not enough to ruin the keyboard.
I’ve cleaned key caps with dishsoap in a plastic container and snug lid. A psyllium husk container worked really well. Could go nuts with agitation then leave them on a towel to dry. This was for a white mac keyboard though so I had to clean the body with qtips and paper towels. its kind of funny how odd cleaning a keyboard can feel. They’re not designed for it, but should be!
I guess I shouldn't be too surprised[0], we used to clean our sneakers in the dishwasher.
And about a decade ago I had a crab dinner served at a friend's house. The guy knew how to cook -- easily the best crab legs I've had (helped by the fact that he knew where to get good product). After we finished the meal, he explained that he cooked them in the dishwasher. I think part of me was grossed out, but it lasted only a few seconds ... they were extraordinary.
Is this the capacitive type or the membrane type? My understanding is that liquids kill the membrane-type model Ms very quickly, which is why they sprouted drainage holes when IBM switched from the capacitive buckling springs to the membrane buckling springs.
(Liquid does not permanently kill the membrane, it's just that liquid gets stuck between the two membranes and can't get out. You can disassemble everything, dry it, and get it working again. Probably. I haven't tried it.)
I have spilled on my Topre keyboards before and there is no fix but to take everything apart and dry the individual pieces. The keyboards are quite well made so can take many cycles of this careful cleaning. To me, that's the best you can hope for; water is not good for keyboards. Though you can probably use Hall effect keyboards under water, if the driving electronics are conformally coated.
The capacitive keyboard was the Model F. Instead of the plastic barrel frame, it uses separate plastic barrels held between two metal sheets, and the little conductive plastic flippers trigger capacitive pads on a PCB. https://deskthority.net/wiki/IBM_Model_F
“This source here” is wrong (as was pointed out in the comments below in 2014). It is just misquoting Wikipedia, which it links to: “In a Model M, the electrical contact is a membrane sheet similar to that of a modern dome switch keyboard. On the older Model F design, a capacitive contact was used instead.”
Go ahead and take a Model M apart. I guarantee you’ll find a membrane sheet.
I will clean my keyboard in the dishwasher every time after I've descaled/cleaned the dishwasher and run a rinse cycle to clear everything else out, so maybe every other month. But this keyboard came from my elementary school, where they'd clean them weekly, because we all know how nasty kids can be. The vast majority of these cleaning cycles came from that school.
Over 800 dishwasher cycles later and the keyboard still functions as if it were brand-new. All I need to do is replace the PS/2 cord which has worn out at the strain relief.