I'm starting to clean up a very dirty (mainly coffee oils) used machine.
I'm soaking the group head, portafilter, screen, screws, ect in a Joe Glo solution.

What about the plastic parts? I've soaked them in soap and water, but seem to need something a little stronger. Most of the plastic is black and I don't want to risk it coming out with a dull grey look. Any suggestions?

McGuires and other companies make automotive plastic cleaners. Motorcycle dealers and auto parts stores carry similar products. I would think that anything made for clear plastic should be fine.

I've had good luck with Meguiar's products on my car. Some of the speciality items (like clear plastic cleaner and polish) I had to order directly from them. Good stuff no matter where you buy it.

http://meguiars.com/

Soap & water, bakelite knobs are best polished with Simichrome Metal Polish - it's recommended for any phenolic resins from vintage jewelery to telephones, to espresso machine parts.

What;s wrong with Joe-Glo™, Clean-Caff™, Cafiza™, or any number of other coffee-oil-and-grunge-specific cleaners out there? Are those harmful to the plastic parts> Have I been damaging my plastic bits by using the soak from the metal bits to wash them down?
OR am I just getting a bit paranoid now?