Paper shredder gunk removal - How?

[CookieCrunch]

As we have now replaced a rather temperamental paper shredder with new one I decided to dismantle the old one for any useful bits. There are a couple of steel hex rods a motor and some nice looking gears but...

How does anyone clean the grease that's thickly dumped on the gears? It's incredibly sticky, like 2 part epoxy without the hardener. I've tried WD40, clutch and brake cleaner, acetone but still it remains, sticking to anything that comes near it.

Any ideas gratefully received.