If they do not show any visible ware on the sides, the pin still fits tight in the washer and there are not any cracks I would reuse them.  Excessive clearance is what causes the OEM washers to fail.  We make our washers so that there is less than .0005" clearance.  We have rebuilt engines that have had our billet washers in them for years and they are still tight when we tear down the top ends.  We have torn down top ends that had billet washers that were not made by us and some of them had over .010" clearance between the pin and hole in the washer but were ****. 

To date, I have not worked on an engine where the aluminum thrust washer broke and chewed up anything.