Free grains, some several years old

Had a friend give me some uncrushed specialty grains and a 55lb bag of munich malt type I, they were stored in rubbermaid totes and the specialty grains were in ziplock bags inside the tote. My question is how do I know if they are still good to use other than brewing with them?

They still smell/taste good and are crunchy when I tasted them, also some of the roasted barley is sealed in vacuum packed bags. The specialty grains are as follows:
Chocolate Malt 5-6lbs 5-6yrs old
Munich Malt 5-6lbs 5 yrs
Roasted Barley 8-10lbs 3 yrs
20L Crystal 4lbs 3 yrs
60L Crystal 1-2lbs 2yrs
Special B 3lbs unknown

Thanks for your help
Greg

I'd smell them..if they smell "off " then I'd probably not use them...on the other hand, if they smell ok I'd say go for it..I've used grains that were kept the exact same way that were several years old and they were fine.
Just in case, I would have some DME on hand to boost the gravity in case they've lost some of their sugars..although being unmilled, than MAY not be a problem.

Thanks, I was thinking that they would be ok to use. Didn't think about getting some DME in case, that is an excellent idea.