Preservation League of New York State
The Preservation League of New York State is dedicated to the protection of New York's diverse and rich heritage of historic buildings, districts, and landscapes. It actively encourages historic preservation by public and private organizations, agencies, and individuals in local communities throughout New York State and provides the united voice for historic preservation.
I like the White Galaxy Marker very much for writing on dark paper, and I have used it to cover another color when I needed to disguise a mistake or simply change effect.
For example, I bought an ornament with name SCARLETT spelled on it and by covering the last 't', I was able to give this to someone with a cat named SCARLET.
If color to be covered is a paint or other pen color, that can make the other color "stain" the white marker tip. This can be avoided if one is sure first color is dry before trying to cover it with white.