The rubber button that switches between streams on my kitchen faucet had perished and it made me sad every time I looked at it. I contacted the manufacturer and they wouldn't sell me a replacement button – they wanted me to buy a whole new $300 faucet. I decided to make my own.
It was tricky trying to maintain an even thickness but I did ok. When I was done I 'polished' the surface with my finger and soapy water which gave a nice smooth finish.
The Sugru was cured 24 hours later and I trimmed off the excess.
I also used my Dremel to grind out some of the silicone inside where the walls were slightly too thick.
It works great and you would never guess that it's not a factory part.