decca norma ?"s for everyone

Ok i tried out a new source and received some deca norma from him with some T-3. Everything seems to be in order with everything except for 2 of the vials of deca had a slightly different color oil inside, yellow moreso then the others. I have deca from a known good source and all but the 2 match up, and even they match up just diff color oils. Both of the vials have the tops sealed and everything seems to be in order but i was wondering if anyone has ever come across some deca that had a yellow tint to the oil, from aging or what. Anyone have a good way of testing the deca to see.
Thanks
Peace out
tuff

Deca does actually have a yellowish tint to the oil. If its totally colourless then I doubt its deca.

Sometimes the deca is more yellow than other batches - not sure why