Depends on what it is. Uniform's are considered to belong to the veteran as long as they are honorably discharged and have completed their commitment.
Other items are generally things that have been replaced in issue or are unservicable.
Sgt. Rafael Peralta ,United States Marine Corps
Company A, 1st Bn, 3rd Marine Regt, 3rd Marine Divison
We will never forget your valor and sacrifice.
Semper Fi !