robo hippy said:

It looks like metal stains to me. I get them on some of my green turned
bowls and think that it comes from metal dust from the grinder. If you
clamped it with water, then it wouldn't be the metal. Try a little
lemon juice or I think boric acid works also to remove metal stains.

Thanks for the input. No, it wouldn't have been metal causing it, due
to the fact that it occurred on glued up veneer stacks rather than the
completed project. I've got a bunch of test veneer glue-ups drying
the in the gar^h^h^h shop as we speak. Maple to maple, maple to
walnut, makore to maple, makore to makore. Clean glue and no foreign
applicator used. I'll figure it out eventually. All this because of
my desire to imbed a reddish detail band - shoulda used black walnut.

I'm thinking that there is something in the makore that is transferred
with the glue into the maple, and the combination of glue and exotic
salts is discoloring the maple. A water wetted clamp-up between the
two species did nothing adverse. We'll see in about an hour...

FWIW,

Greg G.