I need your ideas YA, please help?

So, I am writing a book (I started about a month ago, Im fourteen) and in the book, four teenagers move into a house in a ictorian era. Once inside, they find that the previous owners have glued on and nailed a shelve to the wall, and inside the shelve is a mummifyed pig head painted completly red. Horrifyed, they are trying to cover it up. The shelve looks very out of place, and cannot be taken off or moved. So, what would you do to cover it? PS the shelve is completly sealed.