While trapped in the storm drain, Steve is covered by the foam the giants have put in there. He wipes the foam away and his uniform is clearly wet from the foam. Minutes later when he escapes, his uniform is completely dry and there are no visible signs of the foam.
During the opening sequence a California license plate is visible on the blue station wagon parked in the street.
Looking at the scientist's shirt above the pens and pencils (around 22 minutes) the faded impression of the "Time Tunnel" hourglass shirt patch can be seen.