I have inherited an App desigend by an ex employee

Sometimes the program leaves Excel in the task manager

The programe uses various routines and calling various functions that define
Excel sheets etc (badly named)

I'm finding it hard to follow (my 1st experince of .NET)

is there a way to KILL any Excel instence when exiting the program.

I have come across some posts about GC (garbage collection)
like this
System.Runtime.InteropServices.Marshal.ReleaseComObject(oXLWsheet)
oXLWsheet = Nothing
'System.Runtime.InteropServices.Marshal.ReleaseComObject(oXLWs)
oXLWs = Nothing
oBook.Close()
System.Runtime.InteropServices.Marshal.ReleaseComObject(oBook)
oBook = Nothing
System.Runtime.InteropServices.Marshal.ReleaseComObject(oBooks)
oBooks = Nothing
oExcel.Quit()
System.Runtime.InteropServices.Marshal.ReleaseComObject(oExcel)
oExcel = Nothing
GC.Collect()
GC.WaitForPendingFinalizers()
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My problem is I don't know ALL the Sheets & Books etc that have been defined
/used
program loops about a lot

It would be nice just to do someting like

Loop Until NoMore
   GetProcessByName("EXCEL")
   Kill Process
END