Wolverine's claws have long been pimped as being able to cut through anything. Read any issues of Uncanny X-Men prior to Claremont's departures and you'll see numerous references to that point. Other than his first appearance against Hulk, he's been quite consistant as far as I know in being able to cut through people/things. The only reason he doesn't generally do more than scratch people is because he'd end up maiming or killing almost every character he's fought. That level of violence is generally not done in Marvel and certainly not against a-list characters.