Oxalic acid is a chemical compound of hydrogen, carbon and oxygen. Within the sub-group of  "weak acids" , oxalic acid is relatively strong. It is found naturally in varying concentrations, occuring in many plants such as tea ,rhubard, spinach, cocoa, nuts, berries and beans. Oxalic acid has many uses in various industries, such as construction, joinery, furniture, restration, etc. Oxalic acid can be also be a very helpful chemical to use around the home.