Very greasy shetland fleece

In the summer I was given half a dozen shetland fleeces. I have just got around to washing a few of them. The first one that I have washed is possibly the greasiest fleece I have ever come across. The grease hasn't hardened at all. I have washed it (well lightly scoured it) and dried it and it is just too 'sticky' to card into my usual light and fluffy rolags. I have just given it a second wash and although it is still wet (spun in my spin dryer) I can still feel the greasiness. I hope that I can sort this out, as this grey fleece has got great potential.