User blog comment:Victory awaits/Can witch overpower an Archangel?/@comment-1975828-20160124191700

Personally, I can't say. Since almost every lifeform in Supernatural has a spell that can work against it, there's likely a spell that a witch can discover or master and use it to harm/kill archangels.

It's a possibility. I mean, Rowena knew spells that could transport Lucifer from one place to another, even against his will.