Assume that $\mathcal{X}$ is vertically $\mathbf{Q}$-factorial and let $\pi:\mathcal{X}^{\prime}\to\mathcal{X}$ be a vertical blow-up. If $D\in\Div_{0}(\mathcal{X}^{\prime})_{\mathbf{R}}$ is $\pi$-nef then $\pi^{*}\pi_{*}D-D$ is effective.