Leak sealer crap

[Adelard of Bath]

While at the store I saw that stuff on the shelves, you know the ones that promise to seal all your leaks blah blah blah...but this time I actually read them...the ones that say seals oil leaks claim to recondition rubber seals etc...which I can kinda believe....
anybody know anything about that stuff?

Also there are a couple coolant system sealers that don't have solids in them; I have always believed that they will succeed only in sealing up your heater core, but now that I see these ones without solid stuff in them, I wonder?

Yes I know this is going to open up a torrent of rants from people saying "just replace whatever is wrong" and to those people, I respectfully suggest that they hold their tongue, as this is merely an educational discussion about the sealer products. Obviously fixing the stuff is the only true way to go; that I already know.