Cool stuff, Gilleni. I'd soak it in dilute bleach overnight, allow it to dry out completely, rinse thoroughly, place it in a bucket of fresh water, leave overnight, then rinse thoroughly. Alternatively you could put it in the oven at anything over about 150 degrees for an hour or so. There are plenty of ways to sterilise stuff, do whichever you like. I have bones in with my gilleni too. I placed a spine (backbone) in with mine, it had been in the sun, rain, frost etc for about five years. I put it in the oven, it was completely cooked and dry. It looked like there was nothing but bone there, but when I put it in with the goannas, they became extremely excited and spent the next few days pulling off what looked like strings of cartilage, but were extremely old and worn bits of meat! Yum yum!