It is so simple that it is embarrassing. Forget Lacquer Stix, forget crayons. Testor's model enamel, baby!

I was staring at the thin Bushmaster rollmarks wondering how I could pull it off. The Bushy is my beater, so I wanted to experiment on it before attempting anything on my
precious Mega receivers!
Stuff I used:
*Testor's enamel model paint, Flat Red and Flat White.
*Testor's thinner.
*2 "microbrushes" used for model painting (these look like itty-bitty sponges on a stick).
*A can of CLP (I think I actually used a Hoppe's spray---same purpose).
*A bunch of cheap shotgun bore cleaning pads.
*2 paper cups.
*An "oh, shit" rag.

All I did was put the paint in a cup, and added a little thinner. I took the microbrush and dipped it in. This gives you a drop of paint to work with. Because it is thinned slightly, it runs in to the rollmarks when you touch the microbrush to the surface. It almost filled itself!
I let it touch-dry (about 10 minutes) and then took the shotgun pads dampened with CLP and GENTLY wiped them over the rollmarks in a circular motion (wax on, wax off). This removed any paint residue from the surface without pulling paint out of the rollmarks. Finish with a couple of dry shotgun pads, and VOILA!
The Bushy went so well that the Megas got finished in half the time. I am very comfortable doing it now, and will do it again without hesitation. If you mess up, the thinner and CLP will clean the errors. Don't be skeered!!!