Cleaning the exterior of lenses

[DumbDoDo]

Hello

I have a sweaty palm. So after a while, the exterior of my camera lenses, especially the rubberised focusing ring faded to like dry rubber colour (white-tish fungus look ).

Can any member share tips on cleaning the rubber ring and return it to the black colour like newly bought lens ?

Many thanks.

 

[catchlights]

kiwi it?

or change a new rubber ring.

I don't have sweaty palm, but the lens after extensive handling, also have the same issue, and I don't see as a problem. anyway, the rubber ring need to replace it after some time.