If the method above didn't work: proceed to desoldering. Measure the continuity, and see if it changes if you
slowly play with the slider. It should accuate at a specific point, and not randomly at random places. It should be Continously at 1 ohm. Not 12-24-81-1-21-1-100-2-1241, for example. As you can see, this is f'd.

- High Ohm.JPG (3.83 MiB) Viewed 1704 times
Take the switch appart. Remove exess solder from the leads of the switchplate, and remove said part.
You should have your switchplate on your operating table of your choice.
Using a knife, or simply your nails if you have, scrape off the rivets from the back. You should be take the switcplate now appart.

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It'll fall appart into 4 parts (as you'll see best on scratch_Bot.jpg):
-Plastic piece that interfaces with the leafspring and presses on with a tab onto the:
-Fork with foil with gold plated strip on it, that is being separated with the:
-Separator piece (MIND THE GAP, STAND CLEAR OF THE DOORS, PLEASE!) that goes under the:
-Back contact with dimple in middle that is held on with the rivets of the... plastic piece that interfaces with the lea... (
GOTO10 
)
Please, try using only alcohol (see just above this step) before trying scratching, since it's unnescessary if it has no oxidation. VERY lightly scratch the part of the gold plated part of the foil with a dull knife like mine.DON'T apply ANY force, just a very, very small amount to remove any possible oxidation, and make it shiny again. Do the same range of motions on the other side so that it will be somewhat flat, and gets the same treatment on both sides. This step is not really nescessary, but it might make a miniscule difference. I don't know, only that it worked for me the best this way.

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- Scratch_top.JPG (4.73 MiB) Viewed 1704 times
Next, remove the microscopic metal filings and possible oxide particles that we just made, along with the 30 years of dust accumulation from the contact with your preferred contact cleaner, or some isopropanol, or something that's good for this kind of stuff. I have used denatured alcohol. Clean it with a Q-tip. Do the same on the back contact as well. You'll not need to scratch it. When you're done, wipe them dry with the other part of it.

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- Denalc_bot.JPG (4.79 MiB) Viewed 1704 times
Now we can proceed to puting back the entire thing again. We're done with the cleaning. First, put the plastic part rivets facing up, and carefully drop the fork-foil part in.

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Next the separator

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and the back contact.

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And the leafspring.

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Hold the bottom part tight, untill you insert it into the top housing that you already prepared (and maybe cleaned) wtih the optional click/tactile leaf, spring, and slider. Don't worry about glueing it back together, the top housing squeezes it together very tightly, and the solder will help keeping it in one place too. The parts depending on the switch types might vary, for example SKCL Green sliders are reverible, and make sure NOT to handle the slider too much, if it's been factory lubed, like SKCL Green, Blue, or Ivory:

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You'll just have to put the bottom housing back, clip it together, and test it. It should read 1 ohm, from the actuation continously, without any contact errors. Just fix 1 ohms, no fluctuation, and at one, specific point, relaibly. Right after, or on the tactile bump/click. If it's earlier, you have bent the leafspring too much forward, causing it to register too early. If it's shorted without pushing, you either put it back together with the separator not inserted, or it is not installed correctly, or bent the foil and it touches continously. Anyway, you'll figure it out. It's not rocket science.