Organic stains (coffee, food, tea or tobacco): On granite, sandstone, slate or quartzite you can use a 1/2 teaspoon of hydrogen peroxide or a few drops of ammonia directly on the stain and remove with a damp cloth. On marble, limestone, onyx or travertine use your normal cleaning solution.

Dilute muriatic acid will probably remove the deposits with harm to the amethyst. Vinegar may work as well.

Some people have reported success in removing organic materials such as lichen, clay minerals ore fine grained minerals from quartz and other minerals with the use of hydrogen peroxide solutions. When the solution reacts with the manganese minerals it generates bubbles of oxygen gas.

Pure hydrogen peroxide won’t dissolve anything, but if it is just slightly acidified, it is very good at dissolving black and brown weathering films of manganese oxides.

Bleaching dry rock or a “bleach cure” involves soaking the rock in a diluted solution of water and bleach. The bleach will oxidize and rapidly break down organic material on the surface of the rock. In many cases, you can get a complete bleach cure done in about 7 days making a longer “natural cure” unnecessary.

Spray unwanted moss or algae with a solution of 1 part bleach and 1 part water in a spray bottle. Then, put the small rocks in a 5-gallon bucket or sink and add enough water to completely cover them. Add 1/4 cup of bleach and stir. Let the rocks soak for about two days.

Give Live Rocks bleach bath to keep it clean To cure your live aquarium rock, give it a bleach bath. Make a bleach bath, about 2-3 cups per 5 gallons of tap water. Bleach is the hydrogen peroxide solution that can clean the highly stiff stain spots and smell in tanks and rocks.

Aquarium gravel, decorations, filters, and heaters can also be bleached using the same concentration of water to bleach. You can either spray them or soak them in a bowl depending on what you are cleaning. Just be sure to rinse well and allow everything to air dry completely before putting back in the aquarium.

Bleach kills algae, bacteria and other things you don’t want in your pond. However, it could also kill the fish, turtles and plants living there.

Under any circumstances and no matter how much dirty your tank is DO NOT use dish soap or any other type of soap to wash your tank in it’s entire life. No matter how much you rinse there will be residue of soap on the internal walls of the tank and your fish will suffer and die because of this.

Always remove your fish when using vinegar to clean your tank. Vinegar changes the pH of the water, causing change that can stress your fish, interfere with their body’s protective slime layer, or even kill them, according to Aquariawise.

one of the active ingredients, benzalkonium chloride, is highly toxic to fish (LC50 = 280 μg ai/L), very highly toxic to aquatic invertebrates (LC50 = 5.9 μg ai/L), moderately toxic to birds (LD50 = 136 mg/kg-bw), and slightly toxic (“safe”) to mammals (LD50 = 430 mg/kg-bw)…

Method 1: The clove oil bath

1. Step 1: Catch your fish. Fill up your bucket with water from your aquarium – a gallon will do for most fish, although larger fish might need more.
2. Step 2: Mix the clove oil. You can’t add your clove oil just yet.
3. Step 3: Add the clove oil mixture.
4. Step 4: Add a stronger dose.

Clove Oil (contains eugenol) Around 400 mg of clove oil per litre of aquarium water is sufficient to cause death in exposed fish. The clove oil should be mixed with a little warm water first before adding it to the water and fish slowly.

30 minutes

Detergents can cause severe damage to fish gills, Soap and detergents can affect the critters fish eat, such as insects, by disrupting their cell membranes and by removing the protective waxes that cover the insects, causing them to die due to excess water loss.

Windex and many other cleaners contain ammonia and other chemicals that are bad for fish tanks. Tiny amounts will not affect it in a negative way if you do not apply it directly to the surface, that is most likely why some folks on this site are able to use it on paper towels. I use an asbestos pad soaked in DDT.