Chabad.org — English translation + Rashi
Torah Temimah points to Zevachim 106a (unit 3; single primary locus per emergency Core plan).
E-Daf.com — Zevachim 106a
HebrewBooks / Shas PDF
English: “To the place of the ash-heap” — to teach you that there should already be ash there.
Prior ash required at the burn-site — burning is done at a site that already holds the altar’s ash.
The chatas bull is burned only where altar ash has already been deposited. The verse’s choice of “shefech ha-deshen” rather than a neutral “place outside” supplies the requirement that residual deshen from the mizbeach must already be present at the burning location.