Heat erase pens! Originally intended for erasable notes, these pens have gained popularity in the craft community as a heat erasable ink for embroidery or sewing.
From the manufacturer:
Write, delete, repeat! These erasable gel pens feature a thermo-sensitive, smooth-writing gel ink formula that disappears with erasing friction. They allow users to erase and rewrite repeatedly without damaging documents. The 8-color fine set contains orange, brown, black, blue, red, green, pink and purple.