cometic gaskets
mech1nxh, as far as I can tell might be the only one with "the skinny" on Cometic.
The Powersports industry (motorcycle,ATV, snowmobile, etc.) has been using MLS type gaskets for years. They are not something new. They are not considered re-usable.
As Fishy mentioned, often times the coating of the gasket sticks and peels upon disassembly.
If you need sealants with them, it's because your surfaces are not up to the proper standard/finish quality to run them.
It amazes me how many people want to do some "redneck/home re-engineering" of MLS gaskets...(one guy here mentioned separating the layers and copper spraying all layers)
MLS type gaskets are great, and have their place here in our builds.
They also have to be planned for in our machining.
And of course, this will come up again... over and over...