This is my best place to live in but how can I delete this annoying violin?

First try putting it back on your head and deleting it while its on your head, there are several methods (here is a cheat code: objects.remove_object_set_as_head) If that doesn't work then it looks like you may need to use a script mod to get rid of this using 'destroy object' or go to a back up save if possible in your saves folder (slot file). There is an old script mod on MTS that still functions (enable debug cheats) I think.