Cast iron requires a little more attention and care than your other pots and pans and shouldn’t be put in the dishwasher.
Your good knives dull quicker when put in the dishwasher. Instead, hand-wash your knives and dry with a tea towel.
This is an obvious one. Dishwasher detergent and heat can potentially chip or crack fine crystal. Don’t risk ruining your very expensive and precious items, and just hand-wash ’em instead.
Some wooden items can go in the dishwasher, but it’s best to check with the manufacturer first (if possible). You risk having the wood warp or lose its finish.
Again, it’s best to check with the manufacturer to see if your nonstick can be put in the dishwasher. But in case you don’t know the brand or want to be super careful, nonstick is best to hand-wash. You risk the pan losing its non-stick quality.
You risk changing the color of these gorgeous pans by putting them in the dishwasher.
Soft and Hard Plastic:
Some harder plastics can be put in the dishwasher if the manufacturer says it’s OK; just make sure to put them on the top rack.
You risk getting black residue or marks all over the aluminum item and the other things in the dishwasher.
The dishwasher can potentially eat away at the gold. It’s better to avoid ruining your plates or silverware and simply wash these items by hand.
I’ve definitely put an insulated mug in the dishwasher by accident only to have the space between the outer and inner layer filled with water.
Anything with Adhesives:
Labels with glue can clog and hurt your dishwasher. It’s best to either get rid of the labels before putting the item in the dishwasher (like with glass bottles), or simply wash by hand.