What are people using to sharpen up white writing on tyre wall?
I don't use any pen/paint.
I scrub the raised white areas with pumice stone, such as this: https://www.priceline.com.au/manicare-pumice-mouse-1-ea
Yes that sounds good not a lover of putting stuff on tyre walls usually only use soap and water and scrub brush
There are white pen markers just for this from I presume available from Repco, Autobarn etc also Acrylic type paint.