Will update this post constantly.
The term "scrubbing" or "scrub" means cleaning up an existing sub. By cleaning, it includes using a better RAW (perfect example, GomenRider's Agito releases), removing the honorifics, fix some wordings and remove unnecessary Japanese terms that doesn't have much meaning to the series' enjoyment.
Also, special thanks to @AkoMeiChan for reminding to update this list.
Another special thanks goes to Tom Constatine for helping me updating this list.