To delete a single entity in the default context:

objective-c [myPerson MR_deleteEntity];

To delete the entity from a specific context:

objective-c [myPerson MR_deleteEntityInContext:otherContext];

To truncate all entities from the default context:

objective-c [Person MR_truncateAll];

To truncate all entities in a specific context:

objective-c [Person MR_truncateAllInContext:otherContext];