I dont have one, but if your not going for any kind of status, id leave it. they are blue and i think they are close to the correct color. Id say try acetone, or maybe nail polish remover, as its weaker acetone...but even the polish remover may damage the finish, so id test it somewhere not seen on the helmet to see if it damages the plastic. Ive used this method before to take logo is and such off of stuff. Sometimes it works sometimes it doesnt. But the safest way i think would be to just leave it be.