What is the easiest way to remove old crusty salt/scale stains from aquarium glass. I picked up a 180 gallon tank that had been left empty for 4 years, without cleaning off the glass. It now has salt/scale all over the inside of the aquarium glass. I was told vinegar would work. I tried it and it did remove much of it, but there is still a hazy type of salt/scale stain left. Looks like a smudge, just doesn't have that clear look. Should I just turn the aquarium on each of its sides and let each side soak in vinegar for a couple of hours? Any suggestions would be helpful.