Ok, so, this something no one here knows about.
Go to Dollar Tree, get a bottle of concentrated LA's Totally awesome.
put all of the parts you want to clean in a container.
Add, by volume, 1:1 awesome to water.
let it sit over night.
gunk just falls off, without scrubbing.
I have cleaned all of my keyboards this way. I may make a post about it when my Zenith comes in the post.