I have never removed nail polish from grout lines, so I am guessing here. I suggest testing a small area before committing to anything.
My concern is that All Solv / acetone / nail polish remover might disolve the nail polish and allow it to penetrate further into the pores of the grout once it becomes a liquid.
If the polish is mostly on the surface, Viper Renew might work. Renew actually removes a microscopic thin layer of the grout along with whatever is on top of the grout.
I used nail polish remover with acetone worked about 80% she didn't tell me about the strawberry juice on the counter that was in the grout and the red kid frozen pop on the other counter with lots of red crayol crans all out but frozen pop and 50% of straw jiuce
can I use bleach ?
Use an oxygen booster such as Boost All. Mix the Boost All with hot water and pour on the grout lines if it is a discoloration over a large area. Give some dwell time and clean.
If the disolcored areas are smaller stains, use StainZONE. Apply and let its sit there. Rinse later. May take from 5 minutes to several hours.