A sealed box at an auto parts store is supposed to contain a new part. Some commenters said customers really do return used parts, creating a guessing game for the next buyer who may wind up paying for equipment with no remaining use. Judging from the condition shown in the clip, the used filter had already caught plenty and probably wasn’t doing much to improve the air quality within the cabin. Instead, the old filter became a prop for a brief and harmless gag when the creator placed the used filter inside the packaging that had held the new STP replacement. Before the exchange could turn into a complaint, refund request, or argument over who was responsible, he broke character with a laugh and admitted he just needed to dispose of the used filter.