Norm, the luckiest way I have had is sitting it for weeks in thin oil. I would heat the oil on a stove if I wanted to try it quicker.
My other suggestion (which is more dangerous) is to use a weak (ie max 300nm) impact wrench on a 3 legged puller. the jolting will often break the seal.
Wear a full face shield - I don't know if the pullers like impacts. But I have used this method successfully
