I have a single-handle cutoff valve for both hot and cold water lines of my washing machine. The valve is frozen in the "on" position, after quite some time since being closed. I suspect the problem may be mineral deposits that have frozen the ball in position from the inside, but can't be sure. Any ideas for an easy way to troubleshoot the problem and free up the valve? The valve body appears to be brass, I remember the ball valve moving part was polished, probably either chromed or stainless steel. Would careful heating of the brass valve body with a torch and tapping the handle be worth trying to unfreeze the valve? I'm concerned with cracking the valve body and having a major flood if that happens. Thanks for any suggestions.