"Just some yellow stuff ran into the pan."
Yellow stuff sounds like melted wax to me. I slammed together a box from 1/2" ply that was laying around. No paint. No insulation. Used a single sheet of lexan on a simple frame of cedar for the top. The top could be tighter, but it works like gangbusters. The only thing I'd change is to make it shallower - the bottom pan is too low/cool and the wax piles up in stalagmites. When the wax is all down in my catch pan, I just put it up on top of the melter pan for an hour or so and it melts down into a layer floating on the water.
Here are a couple of photos of the Wax Melter and of my new hives. The bit of yellow stuff you can see at the edge of the melter pan is wax that didn't drip down into the catch pan below.
"Before I speak, I have something I'd like to say. . . . I will try to keep this short as long as I can." Yogi Berra