Nail polish for discoloured tile grout in the kitchen

I have white tiles in the kitchen and the grout behind the stove always gets very dirty and turns yellowy from the oil, etc. It really bothers me. In order to not have to clean it with a toothbrush, I used white nail polish and brush it over the grout. The nail polish brush is the ideal size to paint the grout, it is very easy. All you have to do is to clean the polished grout once in a while with a damp cloth and it stays clean, oil spills, etc. do not have a chance anymore and it always looks clean. You can use the same method for light grout on floor tiles as well.