Assuming they have wood handles, the diswasher will dull and eventually
remove the finish. Being too lazy to hand wash knives, I usually dip the
handles in oil about once a year or so to renew the finish. Usually use BLO
or Danish and one or two dippings + wipes usually renews the finish pretty
well. If one gets scuffed a bit a light burnish with fine steel wool,
before oiling, will clean things up.

RonB

wrote in message
ups.com...
Just bought the wife a nice set of Kitchen knives for Christmas, and
had heard
the advise to hand wash them only, I suppose because the granular
dishwasher detergent
might dull them.

Truth or wives tale??????