One of the chief pleasures in Anne Sexton's poetry is her word choice. The choices often do double duty, denying and affirming a thing at the same time, or referring to two seemingly disparate aspects.
In "Music Swims* Back to Me", the repeated title highlights this pleasure. Music is not a literal swimmer, so you have a curious mix of personification and synesthesia. It also represents a wave of crazy memory that overcomes and overwhelms. Likewise, "the strangled cold of November" describes both the kind of cold, but the effect these memories have on the persona. The "stars are strapped in the sky," presumably locked in place amid the heavens but also like the persona.
In "The Bells", "the circus poster is scabbing off the concrete wall" where scabbing describes its decay but also an old injury. The "boarded sky" suggests a sky that cannot be crossed (although it is).
In "Her Kind", the persona is a "possessed witch" which could mean controlled or owned by a spirit or some other entity. On the other hand, she may be full of some quality (i.e. arcane knowledge). Oddly, this is a thing of unusual power over the ordinary as she flies "over the plain houses." "out of mind. / A woman like that is not a woman, quite." It initially denies her womanhood, yet the final word doubles the sense with an oddly slighting and/or augmenting term.
* Note: Italicized emphases mine.