The spacebar comes off fairly easily - there are 2 scissor mechanisms and two metal u-shaped bars that run the whole length of the spacebar. Comes off if you gently lift at the left edge and the then the other end. Putting it back on is normally a pain but if the scissor mechanisms are installed properly you can see where the two metal bars go and it all just snaps back into place.
Just give everything a good clean - especially on the underside of the spacebar