Skeleton Remains

[Hulk Hogan]

Bone has the MATERIAL_ORGANIC flag, by default you can't do anything with them, you'd have to make an alloy with it, but since you can't put organic material in the smelter or auto-loom (at least, I don't think you can), you can't combine it with anything. Blob you can use because it has the MATERIAL_CRYSTAL and MATERIAL_CLOTH flags as well.

bones could be given the material_crystal flag, they are partially made up of calcium phosphate crystal. https://en.wikipedia.org/wiki/Hydroxyapatite

I believe changing it to material_crystal would just allow you to craft windows.