If doing this in python is an option for you, you could use pyonepassword for this. Tried it out just now, and have the (relatively minor) changes required implemented in a local branch. If useful. I could cut a release supporting this.

Example:
```python
from pyonepassword import OP

vault = "Test Vault"
op = OP()
item_list = op.item_list(vault=vault)
for item in item_list:
op.item_delete(item.unique_id, vault=vault)
```

Worth noting, we're deleting one item at a time, so it's about ~1 sec./item, so not super fast. Also I don't know if you'll hit any throttling issues from 1Password; each item_delete() operation is actually two operations: a get (to resolve the unique ID) followed by a delete.

With moderately more effort, I could implement batch deletion where you could, say, delete 25 (or whatever number ends up working) items at a time.

So, similar to above, but maybe (this isn't implemented yet):

```python
from pyonepassword import OP

vault = "Test Vault"
op = OP()
item_list = op.item_list(vault=vault)

probably have a default batch size, but override with a kwarg?

op.item_delete_batch(item_list, vault=vault)
```

Let me know if either of those sounds useful.

The first option I could probably get out as soon as tonight. The second, wouldn't be too bad, but might take a week or so.

Zach