If you have at any point had to put a bike chain back on, you will know that it is almost impossible to do this without getting some of the chain grease on your hands.
Gyre and Gymble has a neat trick to remove the grease without leaving your hands red and raw from scrubbing.
All you do is wash your hands with Castile soap and warm water. Then add a couple of spoons of sweet almond oil to your hands, and rub in a washing-like motion with the oil. This should remove the rest of the grease without damaging your hands in the process. It may leave your hands feeling a little too oily, so repeat step one and rewash with the Castile soap, but no oil.
If your hands feel a little dry once finished, add one tiny drop of sweet almond oil onto your clean dry hands, rub in, and leave to dry.