BT BB 163a(25) :דיל׳ גאיז ליה לעילא ומחיק ליה לטיוטא‏ : perhaps he will cut it off [i.e. the document] on top and erase the portion covered with dots
See the entire entry for gzz vb. to shear

BT BB 163a(25) :ומחיק ליה לטיוטא‏ : he erases the dotted portion
See the entire entry for ṭiyyūṭ, ṭiyyūṭā v.n.D dotted lines of a document