--- Wear safety glasses for all of the following. ---
I assume you want to remove the bullet without marring it, and that is what makes your task fairly difficult without some of the tools most reloaders have and use. If you know someone who reloads or who has a "kinetic" bullet puller, that is your best bet. If not, you can try pulling the bullet out with a pair of pliers. Be sure to wrap some heavy material around the bullet to prevent marring it (e.g., leather or maybe a small tube of aluminum or copper.) The bullet should come out without a lot of effort.
You can pour the powder on some grass, it's a good fertilizer. Of course, in that small a quantity it won't do much good, but it won't harm the grass. Or - you can light it. That's what I would do. Pour it on a rock or a tin can and simply light it with a match being careful not to be directly over it. It's always an eye-opener to see how slowly smokeless powder burns when it isn't under pressure.
To make the primer safe, the best method is to fire it in your rifle. Any other method
may leave the primer unsafe. The other methods include dropping some oil or WD-40 in the case.
Getting the bullet back in the case and making sure it stays there without a reloading press could be tricky. You might try using a small copper or brass tube that fits only over the tip, and then lightly hammer it back in the case. The problem is that the case has been enlarged and the fit won't be as good as it would be if you could resize the case neck and press the bullet in.
Good luck - and don't try taking your new keychain to an airport.
[Edit]
esheato and I were posting at about the same time, although he was much faster.
Since we both said just about the same thing, you now have confirmation on the methods available.