Quoteing Art Eatman;
You might soak the bolt overnight in a pan of gasoline and try this again.
Please, Please don't soak anything in a "pan of gasoline". You are setting yourself up for a very dangerous fire hazard. All it takes is for the fumes from the gasoline to make it to an open flame and it is "Instant Fireball".
You will be much better served to use anyone of the numerous "Safety" solvents around. They don't blowup so easy.
Let's promote a little safety in our endeavours.