In memory of ......
Is your pet deceased and you want to keep a reminder? Cremation can be expensive and you only have some ashes. Burying is not alwas an option because you cannot move a grave with you. If you are not squeamish, then maybe a skull is an option for you. Mounting almost never keeps your pets expression as it was, a skull doesn't have the goal to look like your friend did!
Harris hawk from falconer / woestijbuizerd van bevriende valkenier
What with the other remains?
They can be disposed of in the same way they would have if no skull is sourced. They can be cremated or disposed of as animal waste material like they would have via your veterinarian.
IS it clean?
Yes, the final step after degreasing is whitening with hydrogen peroxide. This makes the skull sterile when it comes out of this solution since bacteria or other critters are oxidized.
Why would I do this?
A jar with ashes has no monetary value, a grave neither. A skull has a decorative value and can be passed on to people who didn't know the pet later on, your money can be recovered if you like.