http://www.roebic.com/foaming-root-killer.shtml

Tips--

. Don't store it where it can't stay dry, or you may have to break up the caked product with a knife. It needs to enter the toilet as a powder.

. You will need to NOT flush for 8 hours after using it-- so choose your time of day wisely and hang a sign to remind yourself not to flush no matter what else has gone in there (put used TP in the trash to avoid a clog when you do flush). And that's the whole house, not just the toilet you flushed it down. No laundry/dishwasher either.