Jack, this works beautifully. I do this all the time:
-buy some Pine Sol
-use a small container to put the head sculpt in which has a tightly closing lid so everyone doesn't get a sniff, this gan be overpowering
-fill the container so that the sculpt is fully covered, the leave overnight
-make sure you put a rubber glove on the hand that ill be holding the sculpt, then scrub with a dental brush
-repeat if necessary. Don't have to leave it overnight for a second soak, an hour or two should do
-rinse & scrub sculpt with dish soap & warm water, using the dental brush again.
-now you should be ready to prime.
Note: always use surgical gloves to handle the head, dish gloves can sometimes leave ribbed marks on the sculpt that will need to be removed. Also wear them when placing the head on a post to paint, don't want to get oil from your hands on the sculpt. Also wear them if airbrushing the head, protects your hand if you have any small cuts, as well as when clear coating, don't need a laquer on your hands
pm me if you have any questions or need any help, ok