Awhile back there was a tear down video posted that showed someone using vice grips to remove stuck valves. I was unimpressed with that procedure as it pretty much requires new valves not to mention it makes a forensic analysis of the valves tough to do if they are all chingered up by vice grips.
So when I got my core 230 to build it I decided to find a good way to unstick the valves that would not render them useless in all but the most hack builds. I tried a few things like penet