I have a pair of MXCR since ages but I never investigated whether they are rebuildable.
After a full winter, I thought it was the right time to service them just to discover that they are not serviceable.
I was slightly annoyed (I bought a rebuild kit just for them...), however it is actually possible to tear them apart, clean, lube and close them again. Perhaps they won't last enough for a third service but for sure you might be able to prolong their life
This is, roughly, the kit I used, along the pedal itselfç
Main topic is summarized in the below picture: the spindle is rolling over a very small set of ball bearings.
The process is somehow straightforward. Open the pedal, removing the plastic cap (which is normally a bolt on item but for these pedals is just a simple cap pressed on the hole).
Remove the nut) as you'd do with a usual Crank Bros pedal.
Given the status of the spindle,
I don't think that the pedals may survive another service, however there are a couple of takeaways I can share.
This type of pedals (along with their Candy-type cousins) are serviceable.
Tightening the closing bolt (or loosing it) may reduce any play.
Last but not least, there is another (maybe easier) way to help prolonging the life of your MXR pedals. Without opening the body, you can drill a little hole (3mm should be enough) on the plastic cap and, using a grease gun, injecting as much grease as you can (Mr. Cunningham, we all owe you).