Valve Damage Question

This was an e-mail I sent to some of my gearhead friends today regarding the repair of my 1981 Toyota Tercel "Bopper":

Hi all,

I am finally putting Bopper back together and am almost ready to put the head back on the engine. Turning the head upside down to clean off all the old baked-on gasket material, I noticed one of the valves, third from right in attached picture (with a closer view in another picture) has some weird precipitate on it.

Since the old head gasket had failed and coolant was leaking into the cylinders, I am thinking that this is some weird antifreeze byproduct on the valve. It's very hard to get off.

I don't want to replace the valves, I want to finish this job and start driving Bopper again, but the question is, does this raise any alarm bells for y'all? I was just going to try to clean it as best I can and then put the head back on.  Have any of you seen this before?

Thanks,

Tim

And my mentor gearhead guru Mark's response: 

"It looks like carbon deposits to me.  As long as the valves are seating properly and there isn't carbon build up on the valve stem it should be fine.  The valve might run hotter than the others but that usually is only a problem on air cooled engines w/sodium valves.  Just make sure you scrape off as much of the old head gasket as possible and wipe down with acetone before putting the new gasket on.  And make sure the #1 piston is at TDC.  And follow the torque order..."

Thanks Mark! Anyone on the interwebs have any suggestion as well?