I had an old pocket guitar amp that worked fine, but the plastic casing was broken. I went through my recycling and found an old iced-tea aluminum can and cut off both the top and the very bottom of the can, along with a small hole in the side where the input for the guitar would go. I then carefully removed everything out of pocket amp and soldered/glued it inside the can. I then lined the bottom of the can with insulation and glued the bottom back on. It's a bit tedious to explain electronics, but if anyone is interested to know exactly how I did this I'd love to walk them through it!