I have an old enclosure with TONS of water stains. So to remove them I had to use some chemicals that might be harmful to my cresties. So how can I successfully remove the harmful chemicals?
The water stains are gone but the tank still smells like chemicals? Water will eventually dissolve whatever is left behind. I'd leave it sitting full of clean water over night then leave it in the sun for a bit. That should rinse and 'burn off' anything harmful...