In another thread, there was a question about using masking fluids to write lettering in combination with watercolor. I had taken a class on masking techniques at the Letterfest conference in Portland in October, and we had used Pebeo drawing gum as a mask with watercolor and inks, and I'd used it with a broad edge pen (with reservoir) to do some Uncial. I did clean it off the nib right away, and if I were doing a long stint of lettering with it, I would clean it frequently. But there was no gumming up of the nib or any other after effects of using it with drawing gum.
I have not yet tried this with pointed pen, but was perusing the Paul Antonio facebook page this morning and noticed his sample of using drawing gum with both broad edge and pointed pen (Leonardt Principal EF):
Hope you all can see this image. I like this technique and will be playing with it more.
