Hello. I have a stash of never used 60s and 70s mullard mustard caps. Some made in England and some made in Spain (labelled Bianchi) to the same specs. i have noticed that the cement has cracked slightly on some of them. They test absolutely perfect but I wonder if I should use them in amps. I think it's just a aesthetic issue with components that are 50 years old. I guess I could patch them up with a tiny bit of epoxy to stop the crack from getting larger. What do you think?