I don't know what the concentration of oxalic acid in this solution you are talking about is, but I wouldn't use it. The website states it's for rust removal, water stains, etc. Doesn't say for use on cookware. If that's what you want it for, I think you'd be better off soaking the pots and pans in hot soapy (nontoxic soap, of course, like Seventh Generation dishwashing liquid) overnight, then using a scrubbing agent like Bon Ami with a scouring brush or pad, hot water, and lots of elbow grease. Be sure to rinse well with soapy water again to get the Bon Ami off. Your Concerned Consumer, Liora Leah

p.s. I used the above method just recently to clean a very dirty, baked-on-food gunky crock pot, and it worked very well. I actually soaked the ceramic cook part for two days before cleaning it. The outer liner couldn't be soaked because it has the electric cord in it, but I was able to get off most of the baked-on gunk with a scouring pad and hot soapy water.

From the webpage: http://alsnetbiz.com/homeimprovement/oxalic_acid.html

Warning: Oxalic Acid is still and acid and should be treated with respect, do not be lulled into complacency.
In its purified form, oxalic acid is a highly corrosive and toxic substance.
Latex gloves should be worn at all times when using it and it should always be mixed and used in a well-ventilated area.
The gasses given off are dangerous and have been suspected by some in causing health problems.
Always protect your skin,wear a dust mask when mixing ANY powder, eye protection is a must and whenever I am fooling around with chemicals I always have a supply of fresh water available for flushing off spills. If swallowed, give plenty of milk or water, preferably water. Do not induce vomiting. Contact a poison control hotline. If inhaled take a break and get some fresh air. If the nausea or headache persists, contact the poison control hotline. Used Oxalic Acid should be considered hazardous waste and should be disposed of properly.