Hi Maggot,
I agree with you that it's not the best container. My girlfriend bought me one of those just for the tin. (She's great!) I pulled the hinged lid off of the plastic part (the hinge is a separate small plastic piece, itself) and then pulled the plastic top out of the metal body. I was able to mash the now unhinged lid onto the metal body, but it deformed the body somewhat. Still, it could be used in that manner. I hadn't thought of enlarging the hole by cutting the plastic top, until I read your post, but that should work, provided you leave enough plastic "lip" to hold the hinge piece. For any small container I might need, I think I'll stick with an Altoid's Mini Tin, myself, but it was fun to play with, as always.
Stay safe,
J.T.