Q.I have an Indian Sandstone outdoor patio that has become discoloured with small black spots (mildew ?) Now I have read a previous answer that outdoor stone should not be sealed and if its bad stone then "sooner or later you will have to use a jack-hammer." But in the meantime do you have any suggestions as to how to clean it and try prevent it happening again.

A. Try using our mb-9 which is a great mildecide for stone. Dont seal your stone outdoors,Maurizio was right.

Use the mildecide every once on a while and you should be

able to keep it at bay.

Stu Rosen