I know its Hydrochloric Acid but its strength will vary on the dilution that the person applying the Acid to the brickwork makes it.
The mortar between the brick work had a black pigment in it so the strength might have been not as dilute as usual.
The spots are a definite lightening of the woodgrain profile in certain areas. Some of the discolouration occured around the hinges on the doors as well. The frames are in a south facing side of the house and get the heat of the sun.
We have a problem where spotting has appeared on some Woodgrain laminated PVC frames, could Brick Acid have been the cause of this it has happened on the south facing side of a property that gets all the sun.
