If you neutralize the OA with sodium bicarbonate to form sodium oxalate, this is still poisonous. Where you dump it should be considered with care in case a cat or a dog or a squirrel, etc, might walk through it and lick their paws. The reason that this is toxic is that most mammals use HCl (hydrochloric acid) to help break down and digest food. This is secreted in the stomach to a concentration of about 3% HCl and 97% H2O. That's a respectable concentration of acid. The sodium oxalate will react with the HCl forming oxalic acid and sodium chloride (salt). So you're back where you started with a solution of oxalic acid in the stomach of the critter.

So do be careful in your choice for your future Superfund Site.

NOTE: "You've all been brainwashed by would-be environmentalists." For your information, I am not primarily an "envirionmentalist." I am a highly trained organic chemist with a heavy dose of toxicology and proper disposal of chemicals. How long were you playing with the Hg (mercury)?