Pungent odors such as fish or onions may make you want to keep your freezer door closed for good. Instead of worrying if those nasty smells will affect the other items they're stored with, give the entire freezer a thorough cleaning to get rid of the odors for good. Discard ice cubes and any other items that have absorbed the odor.
Unplug the freezer and remove everything inside it -- including ice cube trays and removable shelves. Sniff the packaging for each food item; boxed foods in particular may absorb the odor. If the item smells of fish, onions or whatever odor plagues your freezer, discard it. Any perishables you keep should be stored in another freezer or in a cooler packed with fresh ice -- not the ice out of the stinky freezer.
Leave the freezer door open.
Wash any removable items such as ice cube trays and shelves in the sink using dish soap and hot water, and allow them to air dry. Wipe the items down again with white vinegar if they still smell. Rinse them again after they air dry.
Wipe down the entire inside of the freezer with hot water and a scrubbie sponge. Use baking soda, sprinkled on the sponge, as a mild abrasive that helps remove odors. Wipe down the door or lid gaskets as well, and also the inside surface of the door or lid. Sanitize the interior with a mixture of 1 tablespoon bleach per gallon of water.
Leave the freezer open to air dry for at least 15 minutes.
Wipe the freezer interior down with equal parts of water and white vinegar if any odor remains.
Air it out for several days if you can; otherwise, stuff most of the freezer with wads of newspaper or brown paper bags. Place a few bowls of dry coffee grounds or open boxes of baking soda inside as well, and then run the freezer for several days with the door closed. Afterward, discard the paper and baking soda or coffee grounds before using the freezer regularly again.