Vintage EOS D30 Mode Dial Leaves Residue on Fingers

[MarkinWI]

I have this old camera that still takes great photos at 3.2mp. I’m having a problem with the mode dial. The ridges around the perimeter of the dial are getting soft and leaves black on my fingers when turning the dial. Does anyone know of anything I could apply to firm them up. 
I really should upgrade to something more recent but it still works great. 
thanks Mark

[Danny]

Oops!  We changed it back to the EOS D30.  Most of our digital EOS models have the D at the end of the name.  People mistakenly putting the D at the beginning of the name is so common, we usually correct it without giving it a second thought.  Thanks for catching this for us!