I Have some old hops I was thinking about using in a recipe. The hops were stored in the attic/in my car/under my bed. They are a couple of years old (2 I think?) but smell alright. Do you think it's safe to use or should I just buy new? Hops were originally used to stabilize beer and I imagine are pretty robust. The hops still smell good.....
It depends on what kind of recipe you are thinking of. For example, some sour beers (lambics) specifically call for old, stale hops. On the other hand if you're hoping to make a bright and citrus-y hop-centric beer (e.g. IPA) this would really not be a good choice.
They may smell alright as they are, but it might help to make a tea to see what flavors the actual brewing process will bring out. Simply pour some boiling water over a few hops, let steep for a moment and assess the taste and smell.
Hops also lose their bittering quality over time, increasingly so if improperly stored (hot, exposed to air, etc). This is a varietal trait, too, with some varieties storing very well and some storing very poorly. So you probably won't get the expected full amount of bitterness that you would have were they fresh.
Safety-wise, you should be ok, as long as they never got wet. If there's weird stuff growing, definitely toss them. But provided a dry environment they should at least be safe, especially going into the boil (you might not want to use them for dry-hopping to be cautious).
To me it sounds like they're not going to be in great shape given where they were stored, their age, and the fact that (I assume, since you can smell them) they're open, but there's really nothing to keep you from using them as long as you approve of the taste and smell (and there's no mold or anything). Just don't expect too much.
Safe for consumption, yes.
Chances that the beer will not be what you planned, very high.
As the hops was not stored frozen they would have lost a lot of flavour, aroma and bitterness.
From experience, I brewed an APA that came out very malty because of old hops. Not a bad beer, but not what I wanted to brew.
If possible, rather buy new hops and store the leftovers in the freezer.