I have a 3lb container of lme still with foil seal on it. I think it is 1 yr old. there is no date on container. is it still good or should I toss it...
It is still good. The main issues you may have is that it can darken over time, but still works fine.
I have seen bulk (sealed) LME in my LHBS, that was over a year old. I wouldn't buy it, but when I pointed it out to the guy at the counter, he said that it was OK.
I wouldn't worry about it if it's factory sealed....and I also wouldn't worry about it supposedly darkening over time, unless I was brewing to enter the beer in a competition...I brew for me and mine, color be damned...it's all about tasting good, plain and simple.
It'll be darker & the resulting flavor will be a bit different. But it can still make good beer. I've used 2 year old Cooper's lager cans before,& it came out quite similar to a Salvator doppel bock. So use it a see for yourself.