So I got quite a few duck loads that are too rusty to even try in a shotgun. So I am cutting them open and salvaging the shot, and placing accumulating the powder by brand. Heavy shot, heavy steel, kent fast steel and some winchesters.

Would you even bother trying to reload the powder in anything? I'm thinking some 45 long colt shot shells or something along that line or some light plinking rounds. Or should I just put it on a plant and water it down?

Brand does not quarantee that they used the same powder. It's fertilizer in my book.

I have done the same and always wanted to shoot the powder. I agree with Hal4son, do not shoot it. Not worth it.

Toss it in the flower bed. If the shot is rusty it's junk too, the rust can cause bridging and fluidity problems in the choke. Is it worth risking your barrel?

Yup, pretty much fertilizer for the flower bed.

Not worth the risk over less than a pound of powder.