Limescale Deposit - Brick acid not working

[gregjones]

I have a property where the overflow has been leaking for years. The wall has a large white streak down it. I have tried brick acid in the past but didnt have much luck and it seemed to start damaging the bricks. Any ideas?

[seanmcinnes]

I have exectly the same problem and was wondering if you had found any good answers to the problem?
Thanks in advance.