SecularFrummy –
Only something with flavor is halachicly considered food for purposes of issur v’heter.* Therefore dried out bones and hides which have no (or extremely little) flavor do not constitute meat in the sense that they would be prohibited to mix with milk. This is probably what Sam means.
*The Torah says that non-kosher food should be given to the ger toshav among us. On this the Gemara darshens that only food which is fit to be given to another human being to eat is not kosher; not something which is “not fit for the ger.” Therefore something spoiled or something completely dried out of flavor does not have non-kosher status.