I thought I had found the perfect hole-making tool by using my Dremel. That stood until I was looking for something quiet and sharp. I picked up a Stanley Scratch Awl (from my grandmother's sewing box) and I am amazed. The awl pokes through milk jugs like a hot knife through butter, it poked through hard juice bottles (think the kind grape juice comes in) with some pressure, and it pokes through 2 liter soda-type bottles. The latter collapses a bit with pressure but can be popped back into shape.
I love this awl. No heat needed, no power, and now little shaved bits off hot plastic hitting me from the drill bit! My awl is likely 60 years old, but Stanley still makes them and I think they can be had for about $6.