Whoa, Gregory Smith and all who have similar problems! Opening ancient
food jars and cans is DANGEROUS! You need to talk to a public health
specialist or someone with a similar level of expertise to get advice on
isolation conditions before you even think about doing anything else.
"Puffy cans" suggest that you have a risk of botulin toxin being present.
A fume hood may not be sufficient protection. Bad odors are the least of
your problems.
 
I would think that any jars or cans that are compromised in any way
(puffy, cracked, failed seals) should be emptied in the best controlled
conditions you can get as suggested by the expert you consult.
 
This dilemma came up recently with a house donated to the National Trust
in the UK. As I recall, the decision was made to dispose of all the
tin/jar contents and to display the (cleaned) containers. I can't comment
on how important it is to you (obviously) to keep food in its original
containers in your collections, especially since that is what your museum
is about, but it's always going to be a headache to have food stored in a
collection. Any cracks or ruptures can serve as the basis for a major
pest infestation.
 
Really, please, talk to an expert. Good luck.
 
 
Sally Shelton
Collections Conservation Specialist
San Diego Natural History Museum