I want to rejuvenate the floor in my sunroom. The floor is real brick but as you can see, I need to fill the grout lines and clean the brick. Couple questions:

1) what should I use to back in the grout lines? Does it need to be a powder then I add water or should I mix first then fill the lines? Note the lines can be up to ~1 in deep

2) how should I clean the brick to make it look a uniform color? Should I do this before or after filling the lines?

Thanks in advance!