Talcum powder works like that too. Spread it on the area you wish to draw the oil out and it will become oily. Repeat until it won't pull any oil more out. Helps somewhat to warm the piece up also if practical. If you can get it into an oven as Franz© said, that would be even better. Before everyone went so green, a good hot vat of caustic soda would do the job, but I think everyone is using either vapor degreasing or dry oven degreasing now days, and some with environmentally friendly water based degreasers. With a solvent wash, of course, you aren't going to get very deep into the material, but it's a good start to get the surface oil and grease off.