If you are packing the wheel bearings on a Mercedes, you should obtain the special grease pre-packaged in the correct amount for two wheels. The P/N is A 100 989 23 51 10. I don't remember the amounts but some part of the grease should go in the caps and the rest in the bearings.
Diesel fuel is one excellent way to remove the old grease from the bearings. I suppose fuel oil might work too.
MB wheel bearings have a nut with a clamp on it to provide more accurate adjustment than the old fashioned castle nut and cotter pin approach. Normally, the way to set the bearings is with a dial gauge but if you haven't got one, you can tighten the nut and then back off until you can just spin the washer with your fingers.