chew away
To erode something, often completely. A noun or pronoun can be used between "chew" and "away." Termites have chewed away this whole section of the roof!
chew something away
to gnaw something off; to gnaw at something until it's all gone. You can see what's left of it. Most of it has been chewed away by some animal. Your puppy chewed away the top of my shoe!