Delete comments for specific accounts on Slack at once

Slack informs Slack of a fixed time in Slackbot and sends notifications to Slack when running Python using Incoming Webhooks.
However, as past notifications have been accumulated, it seems that it will put pressure on 10000 free plans.
Is there a way to delete only certain accounts (in this case, Slackbot and Incoming Webhooks) all at once, not by channel?(I couldn't find it well after searching.)

You can use an external language such as Python.

add

Failed to delete(cant_delete_message)->
{'bot_id': 'B01',
'text': 'hoge',
'ts': 'fuga',
'type': 'message',
'user': 'USLACKBOT'}

0 message(s) cleaned.

Messages like this appear and cannot be erased…