Lifespan of Platinum once mixed
Yesterday the girl that teaches photo classes where I work gave me a large number of brown bottles with historic process chemicals. In the mix were a few things that could be useful, except that their age is unknown. I found two bottles (total: approx. 50ml) labeled "Platinum #3" and one marked "Dichromate". They appear to have been stored for some time, and the girl that gave them to me was not clear about their age (she couldn't remember when they were mixed). She seemed to think they would be fine, but I am dubious. They appear to be, at the very least, 2-3 years old and perhaps quite a bit more, but have at least been stored at room temperature.
My question is how long should this stuff last once mixed? I am planning on giving it a shot anyway, but since I've never printed with it before I won't be able to judge the results very well if the chemicals have started to deteriorate. I'm not worried about the dichromate, other than to be sure not to get it on my skin, but I would like to save the platinum if possible.
Thanks in advance!