SB 2.2.24

vaiśvānaraṁ yāti vihāyasā gataḥ
 suṣumṇayā brahma-pathena śociṣā
vidhūta-kalko ’tha harer udastāt
 prayāti cakraṁ nṛpa śaiśumāram
Word for word: 
vaiśvānaram — the controlling deity of fire; yāti — goes; vihāyasā — by the path in the sky (the Milky Way); gataḥ — by passing over; suṣumṇayā — by the Suṣumṇā; brahma — Brahmaloka; pathena — on the way to; śociṣā — illuminating; vidhūta — being washed off; kalkaḥ — dirt; atha — thereafter; hareḥ — of Lord Hari; udastāt — upwards; prayāti — does reach; cakram — circle; nṛpa — O King; śaiśumāram — named Śiśumāra.
Translation: 
O King, when such a mystic passes over the Milky Way by the illuminating Suṣumṇā to reach the highest planet, Brahmaloka, he goes first to Vaiśvānara, the planet of the deity of fire, wherein he becomes completely cleansed of all contaminations, and thereafter he still goes higher, to the circle of Śiśumāra, to relate with Lord Hari, the Personality of Godhead.
Purport: 

The polar star of the universe and the circle thereof is called the Śiśumāra circle, and therein the local residential planet of the Personality of Godhead (Kṣīrodakaśāyī Viṣṇu) is situated. Before reaching there, the mystic passes over the Milky Way to reach Brahmaloka, and while going there he first reaches Vaiśvānara-loka, where the demigod controls fire. On Vaiśvānara-loka the yogī becomes completely cleansed of all dirty sins acquired while in contact with the material world. The Milky Way in the sky is indicated herein as the way leading to Brahmaloka, the highest planet of the universe.