I think we should keep this method for a couple of reasons:

1. we do not test the rake task that cleans up the records so it's better to move all logic in the model so that we can test easily (in fact the tests are not passing anymore)
2. if we keep methods in the model it's really easy for anyone that needs a "custom" behavior to just override the method. The rake task on the other hand has to be completely overwritten.