Rashi: They are Kelim covered with Kesef. This is like "v'Sakosi Kapi" (Shemos 33:22).

Rashi: Tapuchim are like [golden] buttons drawn on Kelim covered with Kesef. Maskiyos is [covering,] like "v'Sakosi Kapi" (Shemos 33:22).

Malbim: Because golden apples are dear, they cover them with silver covers. They are less esteemed, but also they are esteemed. Amidst the covers one sees and understands that there is gold under them. One does not use silver to cover iron and copper! Dibur is the cover of the mind. Hidden matters of the heart and man's thoughts are revealed via his Dibur. When the mind is dear and the Nefesh and its hidden matters are full of honor, also his speech is dear, elevated and clean from all impurity.

Rashi: It is on its base. This is like "Nasasi Emecha Afunah" (Tehilim 88:16) - it is founded and settled in me. Afnav is not from the root Ofan (Yeshayah 28:27, a wheel); if it were, there would be a Patach under the Pei, like "ha'Ofanim" (Yechezkel 1:16).

Malbim: If one speaks Leshon ha'Ra and Rechilus, it is known that under the speech is iron and earthenware, and his Nefesh is lowly. Afnav is a wheel on which speech rolls. According to the thoughts of the Nefesh, so is the speech. If the speech is based on its rolling ¹ , and not more than is proper, it is like golden apples...