Here's a quick guide with pictures.
- Well-lit work area
- Screwdriver necessary to open your mouse (For me it was a Phllips #1 driver)
- X-Acto Knife or very small flat-head jewelers screwdriver (#0-#000 should do the trick)
- Steady Hands
This is a shot of the mouse opened up. I have silenced all of the switches in this mouse, so there were 3 switches at the top (the green PCB to the top-left of the pic) and two on the left side of the mouse (right side of the picture in the top-half of the shell).
This is the main area most will be working in on other mice. See the three switches?
Here's a shot of the side of the switch, showing the mechanism that holds the cover down. You need to use the X-Acto knife to push the clip on the bottom of the cover out past the notch.
This image shows how to open the switches. The blade should be entered between the PCB and the bottom of the switch. From here, you have to push out the bottom of the cover for the switch. Put the blade slightly in between the switch and the PCB (make sure the blunt edge is facing towards the outside of the switch), then while resting it against the switch, push outwards and the clip should disengage.
This shows the side of the switch before disengaging one clip...
And this shows the side of the switch after disengaging one clip. Once you get one side out, disengage the other side. After both sides are disengaged, flip the switch over and then pull the cover off. It is held in place after disengaging both clips by a slight friction, and when you pull it off, you are better off not losing the small white button that sticks out of the top of the switch (hence flipping it over). Place the cover with the outside face down so the white button doesn't fall out of its slot. If it does, just use tweezers to re-insert it before re-applying the cover.
Here comes the fun part. Get your steady hands ready
This is what you should see inside of the switch after removing the cover. Note the bent metal part which acts as the spring. If you press the small metal "bridge" between the two holes in the metal plate (on the left side of the plate in this picture), you will see how the switch works. Use the X-Acto knife to push down on the little metal bridge slightly until you hear the click you are trying to eliminate. You will see that the plate flexes, and once it flexes under enough pressure, the opposite side clicks as it leaves the magnet and touches the contact. Now try pressing down on the side of the plate near the magnet (opposite the "bridge) with the X-Acto knife. Notice that when you press down there is no clicking sound at all. My mod places something between the top of the plate and the bottom of the magnet.
This picture shows the standard gap between the disengaged switch and the pole. The magnet holds the spring up, and the gap, as you can see, is relatively large.
I used ripped and folded up pieces of a coffee filter to buffer the plate from the magnet. After folding, the piece of the filter should be somewhere around 0.5mm thick, at most. After you get a small piece of the filter, cut it to size to fit between the magnet and the plate. I find that using tweezers to place the filter on the plate, then using the X-Acto knife to depress the magnet side of the switch while sliding the filter under works very well. After it's under, depress the switch using the "bridge" and if you're lucky, you will not feel a click. Watch the contact point of the switch to see if it contacts when you press the "bridge" and doesn't contact when the "bridge" is not depressed. You need to experiment with this, just try folding twice or three times, and fold more if it's not thick enough or unfold if it is too thick.
This picture shows the gap after inserting the buffer, and the following picture shows the top of the switch after inserting the buffer. As you can see, the gap between the switch contact and the pole has drastically decreased, meaning you need to press down on each button MUCH less before registering a click. This means you will need to adjust to using your mouse with a lighter touch.
This final picture shows the location of all of the switches in my MX518 (Similar for all of the other Logitech mice with this body design I assume, the MX510, G5, G7, etc). Either way, the switch locations are easy to find, just use common sense. Look at where the switches are in relation to the button on the outside of the mouse.
There you have it. That should be a fairly thorough guide.