Whenever you see code constructed like this...
Range("A1").Select
Selection.<whatever>
you can almost always do this instead...
Range("A1").<whatever>
In your particular case, you have this...
Range("C2:C8193").Select 'select cells to export
For Each r In Selection.Rows
which, using the above concept, can be reduced to this...
For Each r In Range("C2:C8193").Rows
Notice, all I have done is replace Selection with the range you Select(ed)
in the previous statement and eliminate the process of doing any
Select(ion)s. Stated another way, the Selection produced from
Range(...).Select is a range and, of course, Range(...) is a range... and,
in fact, they are the same range, so it doesn't matter which one you use.
The added benefit of not selecting ranges first is your active cell does not
change.