Reference for Chullin 50:5

רב נחמן אמר

- R'Johanan said: Because these [metal vessels] are made for occasions of honour.<span class="x" onmousemove="('comment',' Since metal vessels are reserved for use on special occasions they would not serve the purpose unless they were absolutely finished in all detail and decoration.');">³</span>

Jastrow

Jastrow