Cleaning Soap and Conditioner Dispenser on Whirlpool AWE 6517 Top Load Washer

I have a Whirlpool AWE 6517 toploading washing machine. My question is, the soap and conditioner container doesn't dismantle to be cleaned and has now become very clogged with soap scum and conditioner residue. Can someone suggest something that would clean it? It's been dismantled as far as can be done and soaked in some pretty strong stuff, but is still coated in scum.

By Neal from Orpington, England