Cloth Marking Pens

[rackletang.livejournal.com]

I've been cross stitching for a few months now, mostly counted, fairly simple projects. I've been cheating on the counting by marking a grid on the cloth with a regular pencil (which washes out fairly well, but not completely). I'm about to start a really complex pattern, on pure white cloth, which will be a wedding gift. I don't want to have a faint grid on the cloth.

My question is this: What can you guys suggest as a good way to mark the grid? Do those disappearing ink pens really work? How quickly do they disappear? Would I have to keep reapplying to have the grid on there while I'm working?

I've tried the washout pencils before, but the tips are too broad to effectively mark "on the holes" of Aida.

Help!