I have several european mounts and recently added a couple of more. Do I need to apply any treatment to the skulls to prevent cracking etc over the long term?

As far as preserving the skull, once it has been properly cleaned which would include insect protection, the skull should last a long, long time. Dust it regularly with either a damp detail towel or spray a little Endust or Lemon Pledge on a towel and go over it that way. You never want to "seal" a skull with lacquer or varnish of any kind. The skull is natural bone, and will "breathe" -- for want of a better term -- with the fluctuations in temperature and humidity, and if the skull is prevented from the minute expansion and contraction these fluctuations cause in the bone, then that is when cracks can develop. Just dust them regularly, clean them every now and again, and they will be fine. They will outlast you!

John.

Thanks! I guess I'm surprised that they don't deteriorate in the flucuating humidity of a home. Good news, I guess.