I am using Rails 5 and I want to delete an array of objects. In a previous thread, I read "destroy\_all" was the truth and the light. I had two arrays of objects, which I subtract to get a third array

```
  unused_currencies = all_currencies - currencies_from_feed
  unused_currencies.destroy_all

```

but when using `destroy_all` I got this error:

```
NoMethodError: undefined method `destroy_all' for #<Array:0x007feea8878770>

```