Haven't fired any yet. Thanks and keep up the good work. Ammunition that has been stored in a hot or humid environment can go through any number of types of deterioration. Powder can break down chemically, along with primers. European manufactured ammo from the 50s may be loaded with corrosive primers, as well.
Components are relatively inexpensive for handloading.
My recommendation would be to dispose of the entire lot of such ammunition for safety reasons. Berdan primed cases can only be reloaded with Berdan primers. Removing old Berdan primers requires a special hand tool. Further, it's a dangerous practice to remove live primers. This doesn't justify the small savings involved.