Do the dishes so the sink is empty. Wipe it down after so it's clean & dry.
Take everything out of the freezer and put it all in the sink.
Quickly wipe down the inside of the freezer with a few paper towels.
Quickly put back into the freezer the things which you know what they are and that they are still fresh.
If you have ice cube trays, empty them into an ice container and set them aside to wash them before you refill them with water.
Close the freezer door if you haven't been closing it between things all along.
Evaluate the remaining stuff in the sink. Anything freezer-burned and nasty goes in the trash. Anything completely unidentifiable goes in the trash. Anything that is over 6 months old goes in the trash.
Got anything left? Could you make a nice soup with it? Do you want to eat it? If the answer to both of those is "no". Throw the damn stuff away.
Take out the trash.