For what it's worth, I've noticed my stone rusting a bit if I leave it overnight. I've taken to cleaning it out the water tray everytime I finish using it. I know I have the stainless steel shaft, but even stainless will rust given time. As for the rust on the stone, I'm sure it has little or no operational affect on it. I was amazed at how quickly it would stain. I love my T-7 tho, how fast it works. I am curious to see what it would look like after 7 years.