The old grease is over time separated into thin oil and fat grease. Therfore you have to dismantle the complete gearhoues, clear it and fill it up with new fresh foodsafe grease. I have heard that if you use your machine on a regular basis this will not happen, but if the machine is left inactive for a longer periode this "grease separation" is likely to happen. The foodsafe grease can be purchased on the internet.
Best regrads.
Leif Nielsen (DK), December 2008