When I retract a WSP solution, it is not deleting .webpart from the solution gallery. Is there something I need to do to clean the .webpart files from the gallery and also the web parts that are added to pages?

My feeling on this is if there are any files such as some features, site/list definitions, etc getting deployed by deploying the WSP, those could be retracted. But once the webparts have been placed on a site, I dont think it would get removed from the site just like that. Maybe, the DLL could be retracted, which might ultimately cause some runtime errors. About .webpart files, can you check if the web.config safe control entries are getting removed?BR, PM

yes, the safe control entries are removed. so, when i do a upgradesolution, it will NOT replace the old .webpart file in the gallery with the new one? do i need to do that manually?

Are there any alternatives for automating this manual step?

I dont quite understand MSFT's rationale behind deleting .dll in GAC but not .webpart file. Deleting .dll would make all the .webparts unusable anyways.