I've tried the white paint pens on my BFG's white letters. It sure made a mess, so I wouldn't recommend them.
I finally got them white again but it was a lot of work.
__________________
Gary
Get in, Shu
T Up, Hang
On
!
Member of the Baltimore Built Brotherhood
MY GTO built 4th Week of March 1966
"Crusin' Is Not A Crime"
Keep yer stick on the ice.