For a while now they come out of the dishwasher with small rust spots.

Stainless steel knives can still develop rust. Rust is caused by moisture left on the blade. Rust is not a manufacturing defect and is not covered under warranty. To remove rust from steel, we recommend a product named Flitz. Flitz is a blue gel which helps remove rust, stains, and corrosion from steel. If you decide to use the product, use it only on the areas directly affected by rust. We recommend not letting the Flitz sit on the blade steel for any length of time. After applying the Flitz and removing the rust, please wash your knife thoroughly with warm, soapy water, completely dry it with an absorbent material cloth or towel, and finish with a light coating of cooking-grade oil on the blade and handle cap of the knife. Specific instructions on how to use the Flitz product are available on the Flitz container. Our instructions are not intended to either supplement or surplant the directions of the Flitz manufacturer.

Micro-corrosion, which can result in tiny chips or missing pieces in your knife’s cutting edge, can occur because moisture is left on the cutting edge. Moisture weakens the stainless steel and promotes micro-corrosion. If moisture is left on the cutting edge repeatedly, even normal use in the kitchen can result in small chips in the weakened sections of the edge. To guard against this, wash your knife immediately after use and dry it very thoroughly with an absorbent cloth or towel. Please take extra care to safely dry the sharp cutting edge of your Shun, keeping your fingers away from the edge.

We recommend that you do not wash your knives in the dishwasher. Here’s why: The dishwasher can be hard on all your dishes, but it can be especially hard on knives because they tend to get knocked around during the cycle. Conversely, sharp knives can put “dings” in your dishwasher, too. In addition, when you wash different grades of metal together, brown spotting may occur on the higher quality metals (such as Shun blades). These spots can be difficult, if not impossible, to remove. Finally, many dishwashing detergents contain corrosive agents, such as citrus extracts. Not only can this cause unnecessary wear on your dishes, it can also cause pitting or corrosion on your Shun knives.

For all these reasons, we recommend that you protect your investment by handwashing your knives with a gentle dish soap.