I have tried all the solutions listed:

Application.Quit
varname.Application.Quit
varname.Quit
oApp.DoCmd.Quit acQuitSaveNone
ActiveWorkbook****nAutoMacros Which:=xlAutoClose

I get basically the same results no matter what I do:

Excel visibly quits (the application closes), but an artifact or remnant of Excel remains (if you go to Task Manager, you will see it is still running). If you are running the automation a few times in a row, you will end up getting quite a few instances of Excel invisible but open (as shown by Task Manager), with the only way to close them being via Task Manager. Does anyone know how to resolve this?

Thanks,
Craig