Please don't spray vinegar on marble, please. You WILL etch it, no doubt.Vinegar will etch grout, but will not cause damage, and may be beneficial in lifting shallow stains. There are acid based cleaners that will do a much better job without the smell.
Dump the pine stuff, it leaves a residue that attracts soil.
For the pic in the first post, a high alkaline cleaner with 15-20 min dwell. Scrub the floor with a mal-grit brush on a 175(brush should have 3 different bristle lengths to get into the grout a little better), then rinse. Next an acid based cleaner with 5 min dwell to get up any hard water deposits and brighten up the grout a little. Rinse with a slightly alk solution to neutralize.