I apologize if I am in the wrong place, little new to the forums and to mech keyboards in general.
I've always wanted to invest in mechanical keyboards, but don't really have the funds to do so right now.
However I just started working for the IT department at my college campus and have been coming across quite a few boards that were to be tossed away. So far, here is what I have found:

And the tags for each one:
NMB:

Everex:

Dell:

What exactly do I have here? The Everex board (the middle one in the first picture) is probably my favorite, but the switches feel...
gummed up when typing on it. Any pointers on cleaning/restoring these boards?
Thanks!