If the water from the aqueduct has a high copper content, it could leave a bluish-green residue in the shower and / or on other sanitary fixtures. These stains can also be attributable to the low pH of the water which corrodes the copper pipes, dispersing some traces. If your plumbing pipes are copper and you notice these greenish-blue residues, you should look for more radical solutions to the corrosion problem, otherwise you could end up with several small holes all over the system leaking water. In the meantime, here are some remedies to remove blemishes.
Steps
Step 1. Make a dough
Combine a dose of cream of tartar with an equal amount of baking soda; add a little water to mix the mixture and make it a soft paste.
Step 2. Spread the paste over the stains
Scrub well.
Step 3. Let the mixture act on the stain
It should take 30-60 minutes to get a neat job.
Step 4. Rinse the dough
Check if the stain has completely disappeared; if necessary, repeat the whole procedure.