👉 Get the Chrome Extension
from https://chrome.google.com/webstore/detail/bulk-slack-message-remova/dahaofhkbloejmcijfknenbdgohmmeen
Delete Slack messages in bulk. It supports removing slack messages in public channels, private channels, group chat (your messages only), and DM (your messages only).
Also, it removes threaded messages as well.
ATTENTION:
There are 2 different types of licenses. You must be an admin in order to delete other people's messages.
Admin License - If you are a Slack admin, you must choose this license. It would allow you to remove other people's messages in channels. NOTE: you can only remove your own messages in a DM, however.
Non-admin License - You must choose this license if you are simply a member in your Slack workspace. You'll only be allowed to remove your own messages.