I am trying to install the "Salesforce for Volunteers" package into my sandbox ("Volunteers"). I am running into the following errors "You have exceeded the maximum storage allowed for Custom Settings." I researched this problem and found that I have a custom setting that has 12K entries and is taking up my 10MB of custom setting storage space (Opportunity Rollup Errors). I want to delete all the records in this custom setting. I have tried three things:

1) Exported the Ids of the records and used LexiLoader to delete the records. All 12K failed with the error "CUSTOM_METADATA_LIMIT_EXCEEDED").
2) Delete manually in the UI. This failed with the error "Custom setting limit exceeded. You have exceeded the maximum storage allowed for Custom Settings."
3) This data is actually managed by the Households custom object. There is a page to clear all these records, but it fails because the list (12K) is greater than the DML operation can handle (10K).

How can I purge all these records?

I am trying to install the "Salesforce for Volunteers" package into my sandbox ("Volunteers"). I am running into the following errors "You have exceeded the maximum storage allowed for Custom Settings." I researched this problem and found that I have a custom setting that has 12K entries and is taking up my 10MB of custom setting storage space (Opportunity Rollup Errors). I want to delete all the records in this custom setting. I have tried three things:

1) Exported the Ids of the records and used LexiLoader to delete the records. All 12K failed with the error "CUSTOM_METADATA_LIMIT_EXCEEDED").
2) Delete manually in the UI. This failed with the error "Custom setting limit exceeded. You have exceeded the maximum storage allowed for Custom Settings."
3) This data is actually managed by the Households custom object. There is a page to clear all these records, but it fails because the list (12K) is greater than the DML operation can handle (10K).

How can I purge all these records?