Hello Recently had a new patio laid with natural stone. By mistake some of the slabs were cleaned with hydrochloride and now they are coming out in orange patches. Are they any products that can neutralise the acid in the sandstone? I have tried jet/pressure washing Tried using baking soda mixed wither water. I also purchased some of rob parkers rust remover, initially when I used the rust remover the staining appeared to go away. However, 2/3 days later the staining has returned. Any suggestions would be much appreciated.