How do you make holes in sweater boxes...

I have a drill, but I don't have a soldering iron. That's why I asked. I was hoping I could just drill, instead of going out and buying a soldering iron. I'll buy one of those drill bits, it's probably cheaper than a soldering iron. I don't like the fumes, either and I can't really do this outside. I could probably file and sand any rough edges, I have fine and small files. Sandpaper too. I've drilled hard plastic lots of times, just never this soft stuff they make the sweater boxes out of. Thanks everyone, I really appreciate your replies, they were really helpful.

A ten dollar straight soldering iron from wal-mart does the trick. once it is heated you can fly through the job. as the plastic cools it shrinks a bit smoothing out all holes. I'd have to say by far the easiest way. like a hot knife through butter:gj: