Pit crew tire markings

What is the best thing to use to put the markings on race car tires that pit crews put on them? example: "RF" or "RR" on the sidewall...

Thanks,
Matt

P.S.- the marks on the sidewalls of the tires on this model are what I'm looking for.


http://www.automotiveforums.com/vbulletin/showthread.php?t=897098