Mary Ruefle thinks that, when it comes to poetry, erasure can reveal quite a bit:
"I use white-out, buff-out, blue-out, paper, ink, pencil, gouache, carbon, and marker; sometimes I press postage stamps onto the page and pull them off—that literally takes the text right off the page! Once, while working on an all-white erasure, I had the sense I was somehow blinding the words—blindfolding the ones I whited-out, and those that were left had to become, I don’t know, extra-sensory or something. Then I thought, no, I am bandaging the words, and the ones left were those that seeped out."
(Erasure poem from A Little White Shadow.)