Deodorizing a Puzzle in a Box

Dear Donia,

How do I deodorize a cardboard puzzle from the early 1960s that is in a sealed box? 

Puzzle

Q. Dear Donia,

I am a puzzle collector and I have a cardboard puzzle that is sealed from early 1960s. There is a musty smell inside the cellophane. Is there any way to remove the smell without "unsealing" the puzzle? In the past we have added baking soda and placed the box and pieces in the sun but that was unsealed and easy to do. My collection is 82 percent originally manufacturer sealed and I would prefer not to open it and have it re-sealed. Thanks for any ideas! Thank you, Leandra
 

A. Dear Leandra,

First, if there is an odor, can you see any evidence of mold under the acetate? If so, please wrap the box in waxed paper and freeze right away and then send me a note and we can walk you through what to do.  
 
If there is no visible mold, there are several ways to reduce or remove odors from a wide variety of items, and you have used the first one I like to talk about—baking soda.The problem in this instance, as you mention, is that this puzzle is sealed. It will be difficult to remove the odor in the usual ways as the acetate sealant will not allow for easy airflow to reduce the odor. It is also likely that the acetate sealant is also part of the cause of the musty smell as it held moisture in the box encouraging the growth of the mildew.
 
If you want to remove the musty odor, you will need to remove the sealing acetate to allow for good air flow to allow the baking soda/activated charcoal/Microchamber paper to do its work most effectively. See how to use each of these below as options.
 
The first option is to use baking soda. Put the puzzle box and pieces (open) in a clean plastic storage container with bowls of baking soda and then put the top on the container. Don't sprinkle the baking soda directly onto or into the puzzle or box! This process can take at least a year. The question that usually comes up with this method is how often to change the bowls of soda. Frequency of change and the overall length of time to reduce the odor is all based on how much baking soda you are using,  how much surface area of the baking soda is exposed (shallow bowls or baking pans expose more soda and work more efficiently), how many purses you have, and just how smelly they are. In any event, I would follow the guidelines on the box which is to change the soda every 30 days. This should help to absorb odors more efficiently to help you complete the project more quickly.  
 
You can also use activated charcoal that you can get at pet stores or on Amazon. Activated charcoal is used in fish tanks to keep the water clean and it is also great at absorbing odors. You would use it in the same manner as baking soda but don't need to change it as often (about every 2 months). You can also try the Gonzo Odor Eliminator rocks that you can find on Amazon. If you purchase a couple of these, you can be recharging one while you are using the other. Again, change out every 1-2 months. I would avoid the other odor absorbers you can find on Amazon or in the stores. These often have chemicals that release "pleasant" odors and these chemicals can be damaging to your puzzle. It is best to stick with baking soda or activated charcoal.
 
A more expensive but more efficient method that gives overall better results in my experience is MicroChamber paper. If you get some MicroChamber interleaving paper and wrap the pieces in some and for the box, crumple some paper and place in the box and then wrap the outside of the box with some more paper and place in a safe place but not in a basement, attic, or garage. Change the paper out after one month and each month after that until the odor is gone.  
 
If you want to keep the puzzle sealed, you can try using any of the above methods with the acetate on but it will either take considerably longer to work or won't work at all. However, if you don't mind waiting you can try with the acetate on first and if that doesn't work, you can then unseal it.  
 

Thank you for asking, and if you have any more questions, please don't hesitate to ask "Dear Donia" again.