Our old house has a drum trap on the tub and it's flowing extremely slowly. I've snaked into the trap, but can't get it clear. I've also tried the enzymatic drain liquids, but they haven't help either.

The next step seems to be to get in the drum and clear it out by hand.

I have access to the top of the drum. The cap seems to be bronze (?). A 3/4-inch square head sticks up from the top of the cap, and I'm trying to figure out how to turn it -- there isn't quite the swing for a crescent wrench down in the hole where the trap is. Is there a tool for this? Any other ideas?

thanks, Pat Singleton