Your current solution seems inefficient to me... It sounds like all you're trying to do is clear your sheet....
Try deleting Cells
...
foreach (Excel.Worksheet sheet in m_objExcel.Sheets)
{
if (sheet.Name == "Before & After Lube Weight")
{
sheet.Cells.Delete();
}
}
If still, you want to delete your sheet then remember this is a bad approach...
(Excel.Worksheet)m_objExcel.Sheets[6]).Delete();
You don't need to iterate over a collection if you're using this method to delete the sheet. If some sheets have been added or deleted your collections index may shift so your suspected 6th sheet may no longer be there etc...
The correct approach is (not sure why it's commented in your code)
sheet.Delete();