Yes it's common. My daughter also has aspergers. She has chews all her clothes, all her winter coats and basically everything else she owns or has in her hands even things like like pencil cases, back pack straps, water bottles etc. it's a combination of sensory needs, being anxious and also yet another case of them just not being conscious of how they relate to others. My daughter could be talking to someone and then suddenly decides to mouth her coat and stick the whole collar in and out of her mouth and have it covered with spit. people not knowing her condition go eeew!!
So in my opinion , if you can divert with toys. That will be best but it doesn't always work. At least for us.
