Oregon's expungement law as it applies to juveniles actually requires the record in question to be destroyed. Expungement of a juvenile record requires filling out some paperwork at the Juvenile Court. You should contact the Juvenile Counselor where your case occurred, and the staff ought to be able to help you with the process.
Our office frequently provides representation to clients who are seeking to expunge their adult records of arrest and/or conviction. In the case of juvenile expunction, representation by an attorney is not usually necessary.