Mark, what type or markers are you using? Paint markers or ones made for paper? I use both on interiors. Different brands often need different cleanup solutions. Thats why I keep paint thinners, lacquer thinner, lighter fluid. naphtha, etc. around in addition to various others for acrylic paint cleanup. ISO alcohol can be a good airbrush cleaner between color changes of most, but not all acrylics. ISO seems to clean whatever types of markers you're using. I usually use acrylic paint on interiors because they dry flat. I picked up a set of regular Sharpie markes to try Eddie Mac's process, but I have no reason to try them out now.
I couldn't get over how heavy my Hoffman box was yesterday. It only has my one assembled car but it is packed with arms, tools. & other stuff. If I ever took it racing again, I'd first have to clean it out to make it lighter,