I don't know about removing the chrome rings. I'd have to take a look at how the eyeball is put together. I'm pretty sure I removed the flap portion of the vent in order to replace the foam. The foam, actually a piece of circular neoprene, is sandwiched between two halves. The halves snap together and can be carefully separated. The neoprene can be fabricated from a mouse pad, or something similar, with some scissors and a gasket punch of the correct size. I'll look to see if I can find my old, disassembled vents.