IDK, I used some Simple Green to rinse the tank out, then bought some AirConditioner Cleaner and some baking soda to neutralize the AC cleaner. I just put about a quart of the AC cleaner in and closed the cap, sloshed it around every now and then, while I was tearing down the bike. Before I poured out the AC cleaner, I mixed up a 5 gallon bucket of warm water and the soda. You will need the whole 5 gallons. Then with the soda water handy, I funneled the AC cleaner back into the bottle to reuse later, then immediately poored the soda water in. It will start to foam as it reacts with the AC cleaner, thus why you will need the whole 5 gallons. Just keep pouring it in slowly until just water comes out, then cap and let set for an hour or so. Times up, poor 2/3 of the soda water out, then slosh it around and poor the rest out. Follow this up with some WD40 or Marvles to keep it from rusting again if you plan on shelving it for a while, or just put it back on the bike and fill it with gas.... I will take pictures of the difference, and it doesn't look like that tank on the inside. It looks like brand new. I have two tanks, both were in then same condition on the inside, well the blue one was a little worse, as it was left open for some time.....
