This is essentially the same question as Uninstall nuget packages installed with nuget.exe but that question only has a dubious answer which is incorrect.
Basically, I was mislead by build error messages and bad documentation to download nuget.exe and run nuget.exe install outside any project, only to find out that there is no obvious command to uninstall the packages and that package contents got dumped in whatever was current dir at the time of running nuget.exe install
So how does one properly uninstall packages installed that way. By properly uninstall I mean removing the package contents and any nuget internal state related to the package being installed.
According to a an answer from Microsoft when I posted the lack of a "nuget.exe uninstall" command, "nuget.exe install" outside any project only does a trivial download and unpack, thus doing "rd /s /q some.package.1234" is sufficient.