Getting keyboard out is rather simple if you know how to do it. For mine model I had to carefully withdraw plastic cover above the keyboard(it is attached only with latches) to get access to screws that keep keyboard fixed. After unscrewing them keyboard can be detached from the base.
After keyboard is detached all keys should be removed, very carefully, the process is pretty straightforward. It took about an hour to clean all the keys and a board with bare hands(I wish I had forceps) and old toothbrush.
