knob, nob

Knob or knob means a ( usually ) round piece attached to a door or drawer for a handle --
The knob fell off, and we can't open the door.
One knob is missing; we'll have to buy a new set that will match the holes.

Nob or nob ( rhymes with knob ) means a wealthy person --
They called this Nob Hill because the wealthy built mansions here.
He's a nob; he only speaks to other millionaires.

Now that you know that, you can say --
"This door knob was plated with gold when the old nob lived here."