i would just take the whole part off the dash and
soak it in a bucket/container of evaporust overnight and then rinse it off with thinner
and never even bother to take it apart...
I have one in near perfect condition I am going to be selling off a satellite. I bought a dash pad off ebay and my car is non ac so I'm not going to use it. Not sure if you'd be interested or not, I'll take pics of it and post later today.
Very interested!