Increasing　generation　of　permanent　magnet　waste　has　resulted　in　an　urgent　need　to　preserve　finite　resources.　Reforming　these　wastes　as　feedstock　to　produce　renewables　is　an　ideal　strategy　for　addressing　waste　and　energy　challenges.　Herein,　our　work　reports　a　smart　and　sustainable　strategy　to　convert　iron　in　magnet　wastes　into　Prussian　blue　analogues　that　can　serve　as　cathode　materials　for　sodium-ion　batteries.　Moreover,　a　method　to　control　feed　rates　is　proposed　to　generate　high-quality　materials　with　fewer　[Fe(CN)6]　vacancies　at　a　feed　rate　of　3　mL　min-1.　The　recycled　Na1.46Fe[Fe(CN)6]0.85　center　dot　0.15　shows　low　vacancies　and　excellent　cycling　stability　over　300　cycles　(89%　capacity　retention　at　50　mA　g-1).　In　operando,　evidence　indicates　that　high-quality　Prussian　blue　allows　fast　sodium-ion　mobility　and　a　high　degree　of　reversibility　over　the　course　of　cycling,　although　with　a　three-phase-transition　mechanism.　This　study　opens　up　a　future　direction　for　magnet　waste　created　with　the　expectation　of　being　environmentally　reused.