Description from extension meta
Comment Janitor is the solution you've been looking for to remove the infestation of bots in YouTube comments.
Image from store
Description from store
There are two ways to use Comment Janitor.
1.) Default Settings: The default setting for Comment Janitor is mainly focused on the filtration of bot comments in YouTube videos which often use non-standard characters, embed links, or do other alterations to get around YouTube filtration. Most profanities will not be filtered on this setting.
2.) In the 'Extension Options', you can adjust the intensity of the filter. If you choose to enable the intense filter, it will filter all incendiary terms or phrases from a list I found online. Note that this filter is quite sensitive and is generally only recommended if children are using the device. If not enabled, the default behavior is primarily focused on filtering bot comments.
For those who are tech-savvy, you may view which comments are being filtered by opening your browser console. Here, messages that were flagged by the filter and have been hidden in your comments section will be printed.