I had some gardening lime that I used to neutralize it. Once the fizzing stopped I poured it down the storm drain. Just go to your home store and buy some lime and add it to the used up water/acid. I had a 10 gallon bucket of water/acid mix of which was only about 1/2 gallon of acid. Most of the water came from when I flushed the radiator out. I used probably 3 cups of lime.. not sure exactly since I did not pay that much attention.

I just did a search on how to dispose of it and found that suggestion.

88 Montero, 2.6 Black