I've got a couple of pounds of IMR 4350 that a friend gave to me several years ago. It doesn't smell acidic or have a pungent odor to it but when I pour it out of the cans into another vessel it emits a very fine, rust-colored dust that clings to anything it touches. The inside of the cans show no obvious signs of rusting. Is it still useable or is it a spontaneous-combustion scenario waiting to happen? Is it time to pour it on the lawn or flower garden??
Thanks
Jon