How do I remove the keys on a Logitech MK700 keyboard to clean properly?

SOURCE: logitech cordless keyboard erratic after cleaning keys

seems to be that you may have accidentally swept some dirt underneath the keys.
try pressing each key individually in word and narrow down the affected key or keys, then remove the affected keys (using a keyboard key removal tool, or very carefully by hand) and clean underneath the key with a small dry clean brush both under the key and the board section it lay in, then replace the key and type the key again, if that has no luck then try the process again.

hope this helps

kev

SOURCE: Logitech wireless keyboard not working

After changing the batteries and cleaning the corrosion out of the battery case, I pressed the connect button on the Logitech receiver, then the red restart button on the underside of the keyboard and it was fixed!

SOURCE: S520 Logitech Keyboard keys are

This keyboard is horrible. Several of the keys stick or will not work.
I called customer support which was not very helpful. They told me to take the batteries out of the keyboard then retry the keyboard and if it still did not work return it to the store I bought it from..
I like the set up of the keyboard but? to bad it does not work.
As I am typing this with my old keyboard because I can not use the the s520

SOURCE: Four keys not working on gaming keyboard

i had this prblem before, bought a new one thinking it was broken. Two days after I got it i found a forum post from someone with this prblem too and a solution they had was this;

to uninstall all the logitech software from the computer and then unplug the keyboard from the USB and then uninstalling the keyboard frm Device Manager. shutdwn, plug the USB back in and then startup again.

I tried it and it worked ! I'd just bought a new one for nothing :s

SOURCE: replace key on logitech illuminated keyboard

Since this happened to me accidently a few times and I saw this thread, I thought my 25 cents could help others. I like the keyboard and it is troublesome to send it back for repair for a little thing like this. In my case, I was left with the square black key top and a pair of white hinges detached. You should replace the hinges properly in the base board first and after that press the key top gently and uniformly until you hear a couple of clicks. Make sure you are not irritated when you start this job and do not apply extreme force. It needs a little patience and fiddling. Unless you are lucky or an expert, it takes a number of times until you get it.

The two hinges need to be inserted in the metal clips of the base only after they are put together, not individually. Each hinge has two little rods on the narrow side and two little rods on the wider side. The wider side rods face up and will attach to the key top later. By now, you should be sure which rods of the hinges are up, towards you. Next, the hinges have to be attached to each other in the middle, like a foldable beach stool. You observe that one of them has a middle pin on each side, whereas the other has a corresponding cavity in the middle.

At the time you attach the hinges to each other in the middle, it has to be in such a way that the top part of each of them is smooth, that is, the part that will contact the key top. The side of the hinge that contacts the base has a little tongue between the two narrow rods. This tongue should face down in both hinges. You are now ready to place the little beach stool in the keyboard base.

In my case I inserted the hinge with the open part into the right metal clip and next inserted the rectangular opening to the left metal clip of the base. Whichever you do first is easy, but the second one might need a little help with a tiny screwdriver, or a tool with a similar effect. You might need a few attempts.

Now, your little hinges are attached to the board base and are not flat. They actually look like the legs of an open beach stool. Note which side of the key top is correct, it is annoying to go back to the beginning because you put the character upside down. It is time to press the key top gently and uniformly until you hear a couple of clicks. Unless there was serious damage to the board base or the parts we just mentioned, the key should work as smooth as the other keys.