Plugin removal leaves traces of it's activity in database

[bighatnohorse]

I used this plugin. After using it I deactivated it and then deleted it.
The database should have been restored to original condition.
Next, I exported the database to a sql file so that I could examine it.
I searched the database sql file for name of the URL that I was attempting to migrate to.
There are four instances of the "migrate to" URL left in the database.

The removal of this plugin is not clean.