To answer the question How to delete specific columns in vba for excel. I use Array as below.
sub del_col()
dim myarray as variant
dim i as integer
myarray = Array(10, 9, 8)'Descending to Ascending
For i = LBound(myarray) To UBound(myarray)
ActiveSheet.Columns(myarray(i)).EntireColumn.Delete
Next i
end sub