Hood - clear lens (chipping/grinding, no sparks/slag in eyes)
flip section - tinted lens
Grease pencil
The next time the sun and moon (full or close to it) are in the sky at the same time
turn to the moon and draw and circle on the clear lens around the moon while looking at it with the hood on.
Flip the tnted lens down and look at the sun.
The grease pencil mark should still be there.