If you are going to wash your quilt top, the best marker I ever used that comes off everytime in washing are Crayola washable markers (the finest points). It's made for children to get it all over their clothes and come out. It does come out. The only time I had any problem was with the brown, and that came out with the second wash. It does not come back under any situation. So if I were marking a white fabric, I would try it with one of the lighter colors and do a test before marking the quilt. I've even ironed over it and it still came out.

Verithin Pencils by Prismacolor color GOLD for lights whites, and Pat Campbell white chalk pencil for darks,
The only markers that remove completely are Prismacolor Verithin Gold and Pat Campbell white .
I don't recommend any other color, pen or chemical pen as I haven't had success with removal.
My motto, do whatever works while doing no harm. If you wash your quilts after hand quilting you can spot treat areas that were marked with a heavy hand with Pamolive green dishliquid. My personal preference is an antique look, so I wash when I finish hand quilting. The Verithin Gold removes completely even when I have been heavy handed with my quilt designs. To test the Verithin Gold pencil I marked a 45 x 60 piece of white muslin and quilted it as a wholecloth quilt. All marks came out.

The manufacture has stated multiple times that they did not make the pen as a fabric pen and will not stand behind the pen if used on fabric.... They do not want that liability ... The markings will come back under some conditions..... I have also been reading incidents where the ink migrated to other areas of the quilt. I would not use it or I would use it only in places where it would never be seen.

Hope this helps

i haven't used this, but i have friends that swear by the frixion pens, what i have used with success is Sewline Mechanical Pencils, this company in my opinion makes some great products for sewing, everyone I have tried I have been very please with. Good Luck!
Anne

www.amazon.com/Sewline-Mechanical-Fabric-Pencil-Pink/dp/B00RLCGFZE/ref=pd_sim_201_6?_encoding=UTF8&pd_rd_i=B00RLCGFZE&pd_rd_r=16015ef8-d9fa-11e8-ad21-c9b035b72b90&pd_rd_w=ZLJnV&pd_rd_wg=FPDC7&pf_rd_i=desktop-dp-sims&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=18bb0b78-4200-49b9-ac91-f141d61a1780&pf_rd_r=QN60CHF2FNBQ42FYBKDN&pf_rd_s=desktop-dp-sims&pf_rd_t=40701&psc=1&refRID=QN60CHF2FNBQ42FYBKDN

I have a white and blue fabric quilt I plan to hand quilt. It will take me about 6 months to quilt. What is the best marking tool for a white fabric quilt where the markings will stay on the quilt for at least 6 months. I want to be sure the markings come out after that time.