P:

Don't turn anything without a mask. Period. Never. Sure, people do,
and seem to get away with it. Then there are those that still smoke,
too... and at least for now seem to get away with it.

Walnut is nasty on the lungs. A quick google search on wood toxcicity
will surprise you as Walnut is almost at the top of North American
woods. If the chemicals in green walnut turns your hands colors, what
will the micro dust do to the insides of your lungs?

We had a guest speaker at our club that related a story of someone he
personally knew (so not "folklore") that had been turning Walnut for
new furniture and poisoned himself (turning/sanding/sawing) to the
point of going in the hospital in an EMS unit with tremors. He is now
forbidden from any wood work as he has permanent damage to his lungs.

In fairness, he probably inhaled a ton of dust, and maybe was a little
alergic to boot. Hey, but who cares? You might be too!

And now you ask, turn stuff with stuff with mold? Yikes...

If mold, fungus, algae or anything else suspicious is on the outside of
the wood and it will be removed by roughing, I find my oldest can of
spray finish (not good for a project) and spray the suspected areas to
encapsulate and bond the nasties together, then turn it off on the
lathe after after the junk finish is completely dried.... while wearing
my mask/face shield.

Be careful! Have fun! But be safe. With care that nasty stuff
sometimes turns out to be the best suff for wood turning.

Robert

10 fingers and 10 toes after 30 years in the trades