I have spread it out on the lawn, no damage I saw, but as noted above, plastic and the mix end is it really good?
Probably best to burn it.
Slamfire: I don't know anyone says its good forever. If stored right its good for a long time.
I have seen it perfectly good and inspected (and smelled) fine even in some ratty cans.
Not something I would push but did shoot some of it.
Key was the ratty was all outside and none inside.
I have seen it where there were the brown kernels showing up, that got put on the lawn but reconsidering now.
Per Unclinick, I sure would not put it where it could get into a garden.
And you have to be sure if you put it out, that part of the lawn does not get mixed up into a garden at some point.
Just seems more better to burn.