Forbbiding the base material works, as explained in a SCIENCE! thread not long ago. It results in the artifact becoming iron.
http://www.bay12games.com/dwarves/mantisbt/print_bug_page.php?bug_id=5625Explanation of the bug:
- Have a moody dwarf who wants, let's say, rough gems.
- Mass-forbid all but the most expensive rough gems available in my fort.
- Wait for the moody dwarf to finish gathering materials and begin construction.
- Mass-un-forbid all those rough gems.
The key step:
- Accidentally mass-forbid rough gems of the type the moody dwarf was using, because I'm pressing down then F repeatedly and don't notice in time when I reach the diamonds.
- Unforbid immediately, before leaving the stocks screen - but it's too late.
If the gem were being used for anything other than a strange mood, the job would simply be canceled. For a mood, the item is no longer marked with "TSK", but the moody dwarf continues without it and it will not be included in the final product.
Lastly, if it was the base material for the artifact, then it will be replaced with "iron" generated out of thin air. I'm not sure if the artifact then gets the value of iron. If so, this could be exploited, say by causing a woodworker to use "iron" which is ten times more valuable than whatever wood they were using.
I suspect, though, that the "iron" is really just an artifact of the process of generating the string, which sees absolutely no base material and still has to describe it somehow; in this case the value contribution from the missing material is probably zero.
In this case, just kill the bones and destroy them. The dwarf has already claimed bones once, son he will be able to comp`lete the artifact,
which will be made of iron.