From May 16th, 2019 to March 17th, 2020, 33% user give 5-star rating, 67% user give 1-star rating. for Slack Message Deleter chrome extension.
Doesn't work...
Unfortunately, this and other Slack message deleter extensions no longer work. It appears that Slack has changed the format of their URLs, so the extensions can no longer recognize when the page you are on is a channel or direct message. This will require some redevelopment before it works again.
The ONLY extension that I found to be WORKING and doing what I wanted - to delete the messages in a slack channel automatically. Thank you!