1. Wash your hands thoroughly. You do not want to leave any artificial chemicals that you may have on your hands in the aquarium or you could kill the fish. Wash, rinse and dry your hands before starting to clean.
2. Make a paste with water and baking soda. Generally, you can wet 5 tablespoons of baking soda with 2 or 3 tablespoons of water to make the paste. Mix it with the clean rag or your fingers. Add the tablespoons of water one at a time so that you can stop when the mix has a pasty consistency.
3. Wipe the walls and bottom of the aquarium using the baking soda and water paste. Push the clean rag into every corner of the aquarium to remove every tiny bit of residue or dirt that may have accumulated while the aquarium was empty.
4. Wipe down the walls and bottom of the aquarium with a clean rag soaked in white vinegar. This will take care of any mineral stains on the aquarium. If you encounter a really tough stain, hold the vinegar soaked rag on top of the stain for about 45 seconds and it should lift off the stain.
5. Rinse out the aquarium. Use a final clean, wet rag to wipe all of the baking soda and vinegar out of the aquarium. If you like, you can even rinse the aquarium out using a hose.
6. You can use a razor blade to gently scrape the hardest stubborn areas.
