I use the Staedtler Lumocolors on my CRP-1, best thing to use to erase the pen is nail polish remover.
Works a treat, the pen doesnt rub off like chinagraphs do, and you can stick a small bottle of it in your flight bag, my other half has one use nail polish remover pads which are in a sachet which are well handy.
Only minor drawback is that you have to be carefull using it as it will also remove the markings on the CRP-1 itself if you go a bit mad with the cloth.
Speedy
