I read a question about loosening rusted toilet seats, and 3 people recommended WD-40. Finally the last person wrote "I use WD-40 all the time, but for loosening bolts, I think you should use Liquid Wrench or penetrating oil. They are made for this purpose, not general purpose. And control your urge to try WD-40 first, because it will fill what cracks it can reach and IMVSO make it harder for the Liquid Wrench to get past there to where the serious corrosion is. Finally, let sit for 30 minutes, tapping occasionally on the bolts (though maybe tap less hard than with a car, because the toilet can break.) "
Is there a difference between wd-40 and the other two? Is there a difference between Liquid Wrench and penetrating oil? Is the last poster correct?