If you have beautiful telescoping attic stairs, then over the course of their life they will probably experience some wear and tear. Over time, you may notice dark spots that form where the deck has become wet. These are caused by water with traces of iron coming into contact with tannins in the woods. They can actually be removed without damaging the natural color of wood.
Put on rubber gloves. Oxalic acid is safe for you to use (also called wood lye) but it can definitely wipe out the skin or cause pimples on sensitive skin. Clean the stairs. Stairs get heavily oxidized due to all foot traffic. Sweep the area to clean away, and then wipe off with a damp cloth with hard pressure to remove built-up dirt and dust. Make a paste with oxalic acid. In a bowl, mix 1 cup of oxalic acid and approximately 1/4 cup of distilled water. It should make a thick paste. If all the powder is not wet, add a little more water and continue stirring with spatula until you have a paste that can spread, but it is not running.
Rub the stain. Lay it on quite thick, but do not use it all. Moisten and heat the paste. Put a slightly damp, cool cloth over pasta and then press for about 15 seconds with a hot (not hot) iron. Clean the oak rose. You can simply wipe off oxalic acid with a damp cloth, then wipe it down with a soft cloth moistened with distilled water and wipe it with another cloth. If the dark marks are not completely gone, you may need to repeat the process several times.