【Erase】 , 【expunge】 ,  【cancel】 ,  【efface】 ,  【obliterate】 ,  【blot out】 ,  【delete】  mean to strike out something so that it no longer has effect or existence.

【Erase】 basically implies a scraping or rubbing out of something that is written, engraved, or painted. In extended use  【erase】 often refers to something that has been eradicated as if by scraping or rubbing out after it has impressed or imprinted itself on the memory or has become part of an unwritten record.

【Expunge】  implies, possibly through confusion with sponge, so thoroughgoing an erasure that the thing affected is wiped out completely.

Basically  【cancel】  means to strike out written material (originally with lines crossed latticewise), but it also may apply to an invalidating or nullifying by other means; thus, a postage stamp is canceled to prevent reuse, usually with a hand device or a machine that stamps an indelible mark or device on its face; a transportation ticket is similarly canceled with a punch that removes a part of it; a will is canceled by physically destroying it.

In extended use 【cancel】 implies an action that completely negatives something, whether by a legal annulling or by a revoking or rescinding or often by a neutralization of one thing by its opposite.

【Efface】 , more strongly than  【erase】 , implies the complete removal of something impressed or imprinted on a surface.

As a result, in its extended use,  【efface】 often implies destruction of every visible or sensible sign of a thing's existence.

Often, especially in reflexive use, it implies an attempt to make inconspicuous or vague.

【Obliterate】  and  【blot out】 both imply rendering a thing undecipherable by smearing it with something which hides its existence. Both terms are more often used, however, with the implication of the removal of every trace of a thing's existence.

【Delete】 implies marking something in a manuscript or proof for omission from a text that is to be published or distributed. But  【delete】 also often suggests eradication or elimination by the exercise of arbitrary power.