"Clean" is a song by the American singer-songwriter Taylor Swift, taken from her fifth studio album, 1989 (2014). Written and produced by Swift and the English musician Imogen Heap, the track is a steady soft rock, dream pop, and synth-folk ballad with an electronic production. Its lyrics depict difficulty in letting go of a broken relationship.

Initial reviews of 1989 praised "Clean" for the lyrical sentiments and Swift's songwriting, and picked it as an album highlight. Retrospective rankings have considered the track one of Swift's best songs. Commercially, "Clean" reached the charts of Canada and Portugal and received certifications from Australia and the United Kingdom. It has been covered by several singers, and was featured on the set list of Swift's 1989 World Tour (2015).

A re-recorded version, titled "Clean (Taylor's Version)", was released as part of 1989 (Taylor's Version) on October 27, 2023. The re-recording peaked at number 25 on the Billboard Global 200 and entered in the top 30 on the national charts of Canada, New Zealand, the Philippines, Singapore, and the United States.

The American singer-songwriter Taylor Swift had identified as a country artist until she released her fourth studio album, Red, in October 2012. Although Swift and Big Machine Records promoted Red to country radio, some of its tracks feature styles of pop and rock, a result of Swift's desire to experiment with new styles. This sparked a media debate over her status as a country artist. In mid-2013, she began writing songs for her next studio album.

Swift titled her fifth studio album after her birth year, 1989. She decided to make it her first "official pop" record that would transform her image to a pop artist and move away from the country styles of her previous releases. To this end, Swift recruited new producers including the English musician Imogen Heap, whom she called "one of the most interesting and unique artists". "Clean" was one of the last tracks Swift wrote for 1989; she finished the lyrics and melody before approaching Heap to co-produce it. Swift recalled that she was inspired to write "Clean" after spending two weeks in London: "it hit me that I'd been in the same city as [an ex-lover] for two weeks and I hadn't thought about it."

Heap helped to complete the track by playing instruments, and they finished recording it after two takes in one day at The Hideaway Studio in London. The song was mixed by Serban Ghenea at MixStar Studios in Virginia Beach, Virginia, and was mastered by Tom Coyne at Sterling Sound Studio in New York City. In the third part of the listening session at Grammy Pro in 2015, Swift revealed that for the unique instrumentation of "Clean", Heap combined two of her unique instruments, the mbira, a thumb piano, and "then these things called boomwhackers, which are for the percussion."

"Clean" is a soft rock, dream pop, and synth-folk ballad. At four minutes and thirty seconds long, the song progresses at a steady tempo. Jem Aswad from Billboard believed that the electronic production was influenced by Heap's musical style. It incorporates piano, keyboard, drums, mbira, vibraphone, bass, layered vocals, and a groove that is built around percussion. The Telegraph author Neil McCormick described "Clean" as "understated" and "atmospheric". Hannah Mylrea from NME said the song has "chiming soft rock instrumentals", while The Guardian's Alex Petridis wrote that it features "alternately pulsing and drifting electronics".

The lyrics use imagery of a torrential storm to describe breaking from an addictive, toxic relationship. At one point, Swift sings of a past relationship, "You're still all over me like a wine-stained dress I can't wear anymore." She continues, "When I was drowning, that's when I could finally breathe / And by morning / Gone was any trace of you / I think I am finally clean." The word clean is a metaphor with two meanings: clean as in the feeling of taking a shower and as in getting free from an addiction.