Another source of Sulfuric Acid is drain cleaner - you can't use Drano in a clogged toilet but you can use acid. There are some toilet clogs you just don't want to tackle with a snake or plunger. In Cleveland the local brand is called 'Assault' - don't spill it, it's concentrated acid (unlike 38% battery acid) and puts a hole in the bath mat in seconds. Hmmm... in Canada you may have to bring the clogged toilet with you to the hardware store and have them put the acid in it for you.
I'm with Worker - get a junk motorcycle battery - something with plugs - gut it, and have them fill it.
There should be some way of removing the lead sulfate from the battery acid already in an old battery. Maybe plate the lead out with a battery charger and a couple of carbon rods?