How do I remove this from my farm?

Dec 15, 2014 at 5:37 PM
After I retract the deployment of the solutions in the SP2010 Central admin, I get some innocuous but annoying 'Missing server side dependencies" errors, which in turn give me errors when I do a database upgrade:

[MissingWebPart] WebPart class [6445560d-215d-3f59-3919-5c651b3e3f50] (class [ToolbarManager.Processor] from assembly [ToolbarManager, Version=1.0.0.0, Culture=neutral, PublicKeyToken=8e586c4c8b123d97]) is referenced [1] times in the database [Sharepoint_Foundation], but is not installed on the current farm. Please install any feature/solution which contains this web part. One or more web parts are referenced in the database [Sharepoint_Foundation], but are not installed on the current farm. Please install any feature or solution which contains these web parts.

How can I do a clean uninstall?