3. Wooden cutting boards and spoons
Believe it or not, a lot of people wash their wooden dishes because they are either in a hurry or they do this by mistake. For their own safety, you should never put anything made of wood in your dishwasher because the high temperatures and extended exposure to humidity there can cause the wood to swell, which can lead to warping and cracking.
Cutting boards made of wood will lose their protective oils if you use harsh dishwasher detergents. Additionally, keep in mind that wooden handles on metal utensils or pans may potentially be harmed by the dishwasher.
