using expired nutrients?

Whenever i go into my local hydro store the guy hooks it up with free samples and shit likethat, and this last time I went in there he gave me a free bottle of Mad Farmer silica shield and N.U.T.S, only thing that worries me is the N.U.T.S expired in late 2011. I dont want to go in their and ask them about it cause theyve always been so generous and im sure they would just tell me its fine, but could someone tell me if the nutrient is still safe to use, or if its just lost potency or anything like that over time.

The only problem I've ever seen with old nutes is that some will come out of solution depending on the ph and mabey temps to a degree. Bloom ferts are of a lower ph so will stay mixed for longer. Had an issue with some FF veg nutes coming with a 1/8in crust on the bottom, just poured it into a jar, crushed up all that settled out, put it back and kept shaking it periodically for a few days, seems to have gotten most of them back in the mix.