I was just given a box of Ilford Multigrade Warmtone. I've never used this stuff before, and I'm just curious how old it is. Anyway to tell off the box(it's not dated...)? It's a dark burgundy box with what may(?) be a batch code: 64D601C21. I'll find out if it's any good soon enough, but I figured knowing in advance that it was 5, 10, 15(!) years old would give me some insight in the darkroom. Thanks!