Sealing grout post-urination

Question for my ppl who know about home improvement: it is time for me to re-seal the grout in my bathroom floor. Opal went through a phase of peeing on the floor in there. I have scrubbed the grout and the floor, and also mopped the floor twice. The grout is still slightly darker in the places where she peed. Is there anything else I can do to deep clean this area before re-sealing the grout, or should I just go ahead and re-seal?