Ijust changed my OS 91 cam bearings a few weeks ago. Iused a method similar to the grease method.

I selected the largest wood dowel that would fit inside the center bearing hole of the bearing, about 1/8 inch. I then took an old candle, and shaved wax and placed it inside the bearing center hole, and packed with the dowel and a light hammer. Keep repeating, and you will notice the bearing starting to rise out of the cup. It required no heat, and about 12 repeats of packing with wax. The wax moves behind the bearing and exerts hydraulic pressure on the backside of the bearing.