Remove failed builds for a Jenkins job

import hudson.matrix.MatrixRun
import hudson.matrix.MatrixBuild

for (i in Jenkins.instance.items) {
  i.builds.findAll {it.result && (it.result != Result.SUCCESS) && (it.result != Result.UNSTABLE)}.each {
    println(it)
    println(it.result)
    if (it instanceof MatrixBuild) {
      MatrixBuild matrixRun = it
      for (j in matrixRun.getExactRuns()) {
      	println(j)
        j.delete()
      }
    }
    it.delete()
  }
}