Cleaning lenses

[Halfblindphoto]

What do you use to keep the rubbery parts of your lenses clean and fresh?

I've noticed that the zoom and focus ring on some of my lenses started to get a bit grayish.

 

[DRwyoming]

I've used a bit of Armorall on a clean rag or Q-tip for the rubber rings with good results.

 

[bleirer]

I don't know enough to know what might be bad if it migrated to the glass or inside, so I do nothing.