· many items are not dishwasher safe — our cleaning pros explain which things to never put in the dishwasher , like cast iron, wooden spoons, and stainless steel. · the high heat and pressure produced near the bottom rack can crack and melt certain types of cookware. We spoke to a few experts to find out what items to never put on the bottom rack of the dishwasher. · the bottom rack of a dishwasher is not suitable for plastic items, as they can melt or warp due to the high heat and water pressure. What items should not go in the dishwasher? Should you put things in the dishwasher? Can you put a bowl on the bottom rack of a dishwasher? Other items that should not go in the bottom rack include delicate glassware, large pots and pans, and sh arp knives. · that’s because the water flow on the lower rack can be too strong for certain items and can lead to poor cleaning results, damage to your dishes, or even harm to your appliance. Can you put knives in a dishwasher? While you should always check dishwasher symbols, avoid placing the following items on the bottom shelf. This article delves into the specifics of what not to put in the bottom of the dishwasher , providing readers with a detailed guide to optimize their dishwasher ’s performance and longevity. · cleaning experts share their insight on six types of items to never place on the bottom dish rack. Misuse can lead to poor cleaning results, damage to the appliance, or even pose safety risks.