Recently I have had several calls from fabricators who are using a White Out pen to mark granite before cutting. In most cases the white out marks comes right off. That is for most granite, but there are a few granites and some engineered stone where the marks are very difficult to remove. There are several ways to remove these marks. First try taking some steel wool and some polishing powder. Add some water and rub the mark by hand. The other way is to take some WD 40 and the steel wool. Spray some WD 40 on the mark and rub with the steel wool. Of course always test a small spot to make sure you don't do more harm than good.