Hmm, you are already using a funnel....
If the problem you are having is that the alcohol spills out before you can tip the can far enough towards the funnel, here's what I do:
I hold the can and tip it so that the hole on top of the can is at the *highest* point. Does this make sense? Instead of tipping the can so the hole is near the bottom, tip the can so the hole is near the top. This way alky won't spill out till you tip it a lot.