These types should not be stored together. Glass plate negatives are easy to identify because the negative is on glass. The surest test for nitrate film is to take a very small cutting from the edge of the negative, and, holding it with a tweezers over a sink, set fire to it. If it burns quickly with a smell similar to burning hair, it is nitrate base film. If it burns slowly or not at all, it is safety film.
Nitrate film is the most difficult of film to store.
It is very unstable and will deteriorate easily. As it deteriorates it emits gases that will damage the surrounding photographic materials and paper. The gases can even rust steel. It is still possible to get a print from the negative at this point. However, the discoloration will show on the print.