My understanding is that this "polyfuse" adhesive used by HCM is ...

... basically superglue ... which wouldn't be safe on your scalp. They use it to fuse the base to your perimeter of hair. It sticks like ... well, superglue. As your perimeter of hair grows, the piece gets looser and looser, though still superglued to the hair. Human hair grows about a half inch/month ... so you can get an idea of how it would feel at the end of a 4 week run between appointments.

What solvent could remove this ? None, they use clippers to cut it out of your hair, and then glue again onto the growth since your last attachment.

FWIW,
~FB