Hello,
PEG is polyethylene glycol (also called Carbo Wax) and from what I gather is used to preserve "wet" bone specimens (e.g. those that have been taken from wet or damp environments such as caves or rivers). http://www.flmnh.ufl.edu/natsci/vertpaleo/resources/prep.htm#Chemicals The PEG method is also mentioned in this article: http://www.flmnh.ufl.edu/natsci/vertpaleo/resources/locality.htm
Vertebrate fossils can be preserved using acetone based hardeners/resins such as "Vinac B-15" and "Butvar B-76". http://www-museum.unl.edu/research/vertpaleo/musnote2.html Here is an article about someone who used Butvar B-76 on a mastadon jaw bone to preserve it: http://www.cwreplicas.com/mastodon.html
Here is a list of books that you may want to buy that will provide techniques used to preserve vertebrate fossils: http://www.btinternet.com/~kenmannion/fossilpreparationbooks.htm
Here are some fossil collecting resources that might be helpful: http://www.flmnh.ufl.edu/natsci/vertpaleo/resources/res.htm
I would recommend that you contact your nearest Museum of Natural History to find out if they can give you additional resources and guidance since you may be able to bring your specimen to the Museum for a preservationist to see in person. Since your specimen is so old and likely fragile, you'll want to ensure that you use the proper materials and handling to preserve it. When using chemicals, sometimes a process that is used cannot be reversed and may also prevent any other preservation/conservation methods to be used in the future. An Ice Age fossil is a true treasure!!!
Please let me know if you need any clarification of what I have provided and I'll get back to you promptly.
Jan
Research Analyst
Home improvement/repair, dog owner, tinkerer, vehicle maintenance/repair, environment due diligence