I just want to know how can I remove post history? For example my post have 6 revision. But I want to remove 5 of them. They waste my disk usage. OK, I know maybe it is not too much. But if you think about total 10k post with 6 revision that makes 60k. Depends to your editing, it could be waste too much disk for sure. Actually it is not important either it waste too much disk or not. We should be able to delete post revisions anyway in my opinion.