So... following a complete renovation of my basement bathroom, the shower stall has developed a very odd rust-colored stain along the edges of the floor tiles. Regular cleaners don't seem to affect it, and so truly, I have no idea (a) what this stain might be, (b) what is causing it, or (c) how to remove it. Any ideas?
Where are these stained adges, along the wall or out in the middle of the floor? Is this in the shower or outside on the main floor? Is there tile on the walls? May have more questions based on your answers but I am thinking one possibility is that the nails used have rusted and leached out into the grout.