5% Acetic Acid
Sounds very sciency, however, you probably have this product already in your home. It is commonly known as White Vinegar. Cleaning Vinegar is a higher concentration of Acetic Acid (up to 10%) and can cause mild chemical burns.
According to Canadian Regulations this product is not Hazardous.
Check out a MSDS from for 5% Acetic Acid from VWR.