Hi guys. I have had my deer skull in a 10 gallon tank with a 300W heater in for three weeks now. It is almost clean. However it does have some bits and pieces still on. My question is this, How long can I leave it in before it starts to destroy the skull. It is taken longer because I am in Nebraska and the weather is fairly cold and the heater only keeps it up to about 70 degrees. I just don't want to leave it in too long. Would boiling it for just 10 minutes or so help? Thanks in advance.