What kind of silicone pads can the CLYW Gnarwhal use?
It takes flowable silicone, but Modernyoyoing.com made k-pads for CLYW a month or two ago (Jensen’s site it down right now though :()
If your gonna replace it dont buy them, instead look for flowable silicone at local Autozone for sometjing and look up a vid. You can save about $30 if you do it yourself, and its not that hard
Flowable silicone or gasket maker would be your best bet as everyone is saying. 
Takes a little practice and skill but it’s definitely worth it in the long run.