Reference for Zevachim 232:8

גובה מכל שבט ושבט חמשים שהן שש מאות רבי אומר משום אבא יוסי בן דוסתאי בקר [ועצים] ומקום מזבח בנ' וכל הבית כולו בשש מאות

take new [unused] twigs,<span class="x" onmousemove="('comment',' Or, chips. (10) He held that an altar must never have been used for a secular purpose; similarly the wood must not be fragments of utensils, and the flint etc. must likewise never have been used for secular purposes. Hence he told them to seek virgin soil caused by the drying of alluvial mud. - They would then instruct the young men how to offer the sacrifice.');">⁷</span> produce a fire with a new flint, and offer it up in honour of Heaven.

Jastrow