Huddersfield Town's Andy Holdsworth celebrated his new two-year contract with his first goals of the season.
A first-half double sealed the points for the home side in a typical end-of-season encounter.
Holdsworth, a right-back under former boss Peter Jackson, has been employed in a defensive midfield role under Andy Ritchie but he was able to push forward down the middle.
Town took the lead in the 11th minute when impressive midfielder Michael Collins converted Mark Hudson's cross.
It was the first of a string of chances for Collins as Town ripped through a static Orient side.
Holdsworth added the second when he timed his run perfectly to rise above a defender to head home Frank Sinclair's clever centre.
Gary Taylor-Fletcher was twice denied by excellent saves from Glenn Morris and Luke Beckett had an effort disallowed for climbing for a header which looped over Morris.
Holdsworth made it 3-0 in first-half stoppage time when a defensive header fell to him and he fired into the bottom corner from the edge of the box.
Orient, who won just one of their last nine matches, only just escaped the drop and boss Martin Ling released six players in the week as his rebuilding job begins.
The visitors improved in the second half and scored with their first shot on target in the 59th minute. Jason Demetriou cut inside and beat two defenders before drilling an unstoppable shot beyond Matt Glennon.
That strike was the pick of the four goals but it failed to spark a revival. Morris saved twice from Beckett in the second half but the game just petered out as a contest.