Stuck valves

[redondoaveb]

I decided to do a leak down test on my spare motor that's been sitting for a couple of years. All tested perfect except #3 cylinder. I have the upper intake removed but the lower is still on. When I pressurized number #3, air was pouring out of the #3 intake runner. Ok, stuck intake valve. I sprayed wd40 down the runner onto the stems and seats and turned the engine over by hand a bunch of times. I reinstalled the leak down tester and it appears I freed up the intake valve because now I can hear it coming out of the exhaust port It must have been stuck open a little bit but I couldn't hear it before because the intake valve was stuck open more. I sprayed the exhaust valve stems and seats and turned it over again but so far it hasn't freed it up. I'll let it soak for a while but does anyone know of a better penetraring oil or a good way free up the stuck valves without pulling the valve cover or head?