I just cleaned mine yesterday. They really weren't difficult at all to get out, or to get back together. One thing I did notice is when you push them back together at the locking points, they go back together a little easier if you put outward pressure on both mats. Hard to describe, but basically push outward on both mats away from where they meet. I've found that helps them slip together better.
Also, for the cleaning itself, a little carwash soap and a soft bristle brush attached to a cordless drill makes it real easy.