Here is how I camouflage ammo cans. It is quite easy and can be done by spending relatively little money. For paints, I use Krylon Camouflage. It is nice and dull and isn't too expensive. It comes in four colours, but we're just going to use brown and black and the ammo cans are already green. Depending on where you live, you might want to use different colours. If you just use regular gloss paint, it is bright and shiny.It doesn't look too bad, but it doesn't do much if you are actually trying to hide your cache better.
Remember to use spray paint in a well ventilated area!!! This stuff is toxic and doesn't smell very nice!!I cut a basic stencil of leaves out of some cardboard. You could buy one, make one or just use real leaves.
Begin by making sure that you have lots of paper underneath and around your can. I suggest spraying outside or in your garage. Make sure to read all the directions on the can.
I also suggest wearing gloves of some sort so that your hands don't become camouflaged either.
Hold the stencil (or leaves) against the can and spray, move the stencil to a different spot, use a different colour and repeat! Don't worry about drips, it doesn't have to be pristine.
Thats all there is to it!