Casio CZ/ VZ/ FZ - Pro Series

Hi folks, I just joined hoping for some help. A friend made me a "permanent loan" of an old CZ1000. It works but some of the membrane switches are either iffy are just don't work at all. 

I did search this forum for "membrane" and a couple of other things. While I did find a few posts like this one, I found no responses or help. 

So I'm just wondering, is there any conventional wisdom on this? Anything like "spray this stuff on them" or "you can replace them but it's a hassle" or "forget it, it's not worth it" etc.

All opinions are welcome.

Thanks! Scott