To remove Spinach you'll need to do one of the following:
1. Go into Future Meetings-> Auto Record and select Remove from all meetings.

2. If you're using a Spinach email on the calendar invite (for long time users) ask meeting owners to remove Spinach from the calendar events. Due to calendar provider permissions, only meeting owners can remove guests from the events.

For recurring meetings, make sure the meeting host selects the option of "this and following events"