I've used silicon grease in plastic hinges before.
2.
For something like this one would need to thoroughly degrease and then depend upon silicon grease only.
3.
Vaseline, silicon grease, or a silicon-vaseline mixture is used to seal the nerve or tissue in position and prevent diffusion of solution between the chambers.
4.
Flooding was attributed to many factors, one of which was the change to orange-colored silicone o-rings that could swell and fail if third-party silicone grease was applied instead of the Nikonos grease that was petroleum-based . ( Non-Nikon ( third party ) silicon grease was commonly used without problems on black Nikonos o-rings by underwater photographers for several decades . ) Nikon replaced all these floods at first, but in the end, it clearly became not worth the trouble.
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