My sis gave me her old empty aquarium and it's been gathering a lot of dust in the garage, for she's hasn't used it in 2 years. How should I clean this aquarium before I put any fish or ornaments inside? She said that I should not use dish washer soap such as Dawn, to clean it, which frankly I find hard to believe, and that I should just rinse it with water or use salt to clean it. Is this true?