I have been trying to get the grease out of an antelope skull and the progress has been slow. I keep getting a large spot on the top of the skull where the grease bleeds through. I have simmered the skull a couple of times in water and dawn dish soap. The first time I also threw in some borax. My guess is that I have overcooked it and locked in the grease. The last 2 nights I had it in bucket of water and Simple Green but it didnt do much good. I have also had it out in the sun for several days and have also used basic white and peroxide to whiten it. I read in the archives some have had good success using acetone or Coleman fuel for removing grease spots but I could not find any comments on the negative effects to the skull material. This antelope skull appears much more fragile than the bear skulls I have worked with before. Will the acetone or coleman fuel erode the bone? My novelty mount book from WASCO recommends using Polytranspar degreaser so perhaps I should try that. This is for a friend of mine so I would like to do a nice job on it but I also dont want to burn down the house. Any help is appreciated. Thanks. Mike
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As I've stated dozens of times, acetone, Coleman fuel, gas, mineral spirits, et al are simply "solvents" and work by dissolving the grease into themselves. Thus a small grease spot is dispersed over a larger area and not eliminated. Antelop have very little grease as compared to bears and other animals and it's most likely you didn't mascerate it. If you boiled it, you cooked the brain and the natural grease puddled in the skull area now leaving you with this spot. Had you mascerated it, the oils would have floated up and out of the skull. (Ever notice that a skull you find in the desert never has any oil spots?) Set it out in the sun and let it dry. Then take peroxide and bleach the skull completely, paint with Elmers glue.
give Skulls Unlimited a call 1-800-659-skull.
website www.skullsunlimited.com
they will tell you what to do. they helped me with my grease problem in my boar skull
Long story short.. acetone works very well at removing oils and fats from bone. Solvents and soaps both remove oil from bone, they simply do it in different methods.
Museums have a list of various solvents (most a lot more harsh than acetone) that are employed in degreasing of their samples. The ONLY reason I am forced to go with anything other than acetone for degreasing is that Ontario law prevents us from using more than 5 gallons at once. 5 gallons simply isn't enough to degrease large whale bones. For anything that will fit under that 5 gallon limit - acetone is the "grease getter outter" of choice. I'm not in the mood for a lecture, so I won't call it a 'degreaser'...
I haven't found any drawbacks to using acetone outside of health concerns (which with proper ventilation etc are not a concern). It removes the oil from the bone and when the bone is removed from the acetone.. the remaining acetone simply evaporates away - leaving behind an oil free, non smelling, perfect bone.
In a recent set of samples involving some small whale bones, nothing is coming close to doing what the acetone can do. The acetone did in just over a week what all the soapy products have yet to do after 3...
Next time, HEAT your soapy water so the pores will open. That's something you'd better not try with your acetone, however. You'd make a pretty sizable hole up there in Canada. LOL
It really does not matter how you cleaned it, simmered, beetles, maceration...ect. Acetone, or a lacquer thinner that is MEK or acetone based (most are MEK, Methyl Ethyl Ketone based) will properly degrease the skull with no adverse effects. I have found that the acetone based thinner is more efficient but it is also very expensive, I paid $435.00 for a 55 gallon drum last week. Two months ago it was $325.
Despite what George has said solvents do not simply disperse the grease over a large area, they remove it from the bone over time. Setting it out in the sun, letting it dry, and then whiten it is bad advice, it will eventually leak grease again, grease does not evaporate. It needs to be degreased and this is not a daylong process. The easiest way is to purchase 5 gallons of lacquer thinner from the hardware store and put the whole skull in the can. Leave it there for several weeks; even a month is not too long. When you remove it from the thinner dry it for a week in the sun. Just keep using the thinner for the same purpose until it turns dark orange, then dispose of it responsibly. The spot will be gone.
I have been down the detergent based product road and your wasting time and money go with the solvent. E-mail me if you have further questions. Goats and sheep are not as greasy as bears but removing the grease from the back of them above the Occipital Condyle is just as difficult if not more. The density of the area make the removal process much slower.
Be patient, work on something else and forget about it for a while. It will come out.
please keep in mind that using such thinners like acetone can not be pored down the drain or dumped in the back yard.Also keep in mind that the more chemicals you use on the skull the more damage you are causing to the skull.I hope there is a skull left after you get the spot out.unfortunitly tou will here ALOT of different methods of skull cleaning but only 1 out of 30 methods will work for you.Every skull is different,even if it is 2 bear skulls or 2 antalope skulls and the agd of the animal is also a factor.You are more than welcome to e-mail me.I have a simpler,easier,cheaper,faster and safer way to degrease.I do more complete animal skeletons but also work on a few problem skulls.Raven ,ryan toth and mike vaden are excalent people to answer your questions and actually know what they are talking about.good luck.Also krylon is a MUCH better to use to protect your skulls after cleaning,but must be krylon clear matte finish.
Thanks everyone for the comments. Several days ago I purchased the lacquer thinner and I have since removed the skull from the bucket. It does seem to have removed the grease spot (for now at least)but it also appears that it has thinned the bone structure a bit. Maybe its just my imagination? I have used the Krylon Acrylic spray finish on a couple of my bear skulls and was quite pleased with the results. The antelope skull is for a good friend of mine and I think he would rather have a dull finish. I think I will try the Elmers Glue as George suggested. Thanks again for the help. Mike