They apply various chemical tests then rinse the gun off with tap water then they fire three to five rounds, zip it into a bag then throw it in a box which then goes into a climate uncontrolled warehouse which if you’re lucky protects said box from getting any more moist if not well rat urine and rain water will add too your guns “character” until your court date. in the case of a stainless revolver like the Cobra above, such treatment would if you were lucky result in minor surface rust to the stainless parts and the utter, complete oxidation of all carbon steel internals including the main spring, rebound slide spring and hammer nose rivet resulting in a thoroughly seized up if not completely totaled revolver.