So, I am probably going to ask my father to help shove the boot on (since I'll be using his garage), and I bet he'll have an objection to soaking the boot in water. I'm sure he'll think getting moisture inside the can is bad - he's just really cautious about stuff, and it seems like water doesn't belong in there.
So, how can I assure him that it's okay? Why isn't it bad?
OR:
Why use water to warm? Why not other methods like a heat gun/hair drier? I bet because those things could dry out the rubber, which isn't a good idea before stretching.