^Hehe yeah I was gonna say!
With the DIPT, it depends how discoloured it is. It turns yellow/orange fairly easily by exposure to air, but I guess even orange stuff can still be fairly pure (assuming it was to start with) since oxidation products are often brightly coloured and it doesn't take much to make everything coloured. I haven't actually checked the purity of discoloured stuff though. If it's black/dark purple or something then yeah, maybe you should throw it away.
If it's a bit discoloured you should be able to clean it up by recrystallising it from naphtha like you would DMT, assuming it's the freebase.