I have a membership signup/renewal page that also allows for additional contributions using the standard fee table (no price sets). Since upgrading to 4.7.23 the online membership page is showing previously deleted options from the additional contribution fee table. How can I remove these (my understanding is they are stored in a default price set)?
Even when you're not using a price set, modern versions of CiviCRM store the contribution amounts on a Contribution page as a Price Set internally.
CiviCRM doesn't let Price Fields be deleted when the Set has already been used to store data as potentially data loss could occur.
Therefore I think the best option is to disable them, or switch to using a real Price Set.