if u purchase pb blaster from ur auto store u can spray it downt there and it will penetrate the metal we use it all the time at ntb for stubborn lug nuts so dont spray conservatively- how ever u spell it if that doesnt work idk what to tell u but let it sit for like a good 5 min but if they are really on there bad let it sit longer.. let me know if it doesnt work u will be the first