The big ones that are the size of newspaper pages are just that - page negatives. They were used to make the printing plates from which the newspaper was printed. The smaller ones probably are the camera negatives reporters and photographers made for the newspaper.
The page negatives likely would be of less interest to a historical society or history museum than the reporters' original camera negatives. Those are a goldmine to such institutions.
Most libraries and historical museums probably have either microfilm or bound copies of the newspaper, so prints made from page negatives would be redundant. I would check first before recycling them. Yes, they can be recycled for silver content. As someone said above, find out where your local hospitals recycle their X-ray negatives. Silver is considered a heavy metal contaminant in water, so it is best to recycle.