How to clean mildewed rubber trim piece

I have a couple of pieces of rubber exterior trim that have really gotten stained as if by mildew. There is no apparent surface material, no odor of any kind, and a hearty cleansing with soap and water does no good.

I thought my next step would be to use a household cleaner with bleach like 'scrubbing bubbles' or the like.

Have any of you dealt with a similar issue and if so did you have any luck? I either want to clean this properly or determine if it is practical to paint over this trim so it looks clean again.


Thanks for any help,
Stu