Grout Residue Removal How Do You Get Grout Residue Off Of Textured Tile Without Taking Out The Grout From The Lines?

How do you get grout residue off of textured tile without taking out the grout from the lines? - grout residue removal

We have a patchwork of texture in our walls and shower are in the process of solution for injection. so we followed the instructions for cleaning and now it is dry mortar is cracked and has small holes. regrout then a sealer on the new and the first and remains the same. I am desperate and do not know what to do. We have a bathroom and want to end soon!