Re-Silvering Headlight Projector Bowls on E46

Hi - I have a problem with the ZKW HID Xenon headlamps on my 2003 E46 330i.

Last year, I swapped out the inner projector bowls on both sides because the interior silvering on the bowls had become corroded. The headlights were very dim and did not project much light at all.

I was not able to source factory replacement parts for the interior of the lights anywhere, so I ended up buying a pair of bowls off of ebay and using them.

Now, I have the take-off bowls, and am wondering if it is possible to re-silver the interior coating of the bowls to make them like new?

The lights are the optional HID Xenon's by ZKW; car is a 2003 E46 330i / ZHP...

thanks in advance...