I knew with a little help from the Internet it wouldn't take long to find an answer to my question of what am I going to do with all of the grenades I stockpiled in anticipation of the end of the world that did not happen. Yeah, I know these particular versions are made of nylon and mesh and, like, malleable materials, but I think I could saw open the metal on mine and solder on a zipper or something like Hirotoshi Ito does to rocks. I'll call them Change Bombs and sell them on Etsy under the tagline, Make Money, Not War.
However, if you would like a grenade coin purse/key holder combo before my authentic version is actualized, I suppose you could check out the superficial replicas pictured here, available in black, army green, and hot pink. Each has a main zip closure, an interior zip and mesh pocket, and 6 key clips. They measure 4.5" long x 2.7" wide x 4" high.