Heard parchment just does that on its own.

I've run into this a few times with used books for my own club reads, so here's what worked for me. The move is to read the book once through without touching the notes, then go back and skim the margins after you've formed your own views. That way you walk into the meeting with your take already locked in and the stranger's notes just become extra fuel for discussion instead of the main thing. Some groups I've been in actually make it a rule to only buy clean copies, because one person's scribbles can quietly steer the whole talk in a direction nobody chose. If you already read it with the notes in view, no big deal, just own it at the meeting and mention you had a plus-one in the margins. Worst case you got two readers for the price of one, which beats paying new price any day. Your mileage may vary depending on how heavy the notes are, but for me light underlining helps and full essays in the margins get distracting fast.