In article , Pam Moore
writes
On Mon, 8 Aug 2005 20:37:59 +0100, Kay
wrote:

They turn green because light has got to them. Put them back in a dark
place, and they go back white/yellow again.

Kay, I have never heard this. Does that mean that the oxalates (or
whatever) go away?

Solanine.

Good point. I don't know. So I shouldn't advise other people to do this.
I will continue to, since it has never done me or my family any harm.

Googling reveals several things
1) that it builds up with time - so frequent checking of potatoes is
advisable
2) that small doses are tolerated (it is apparently present in potato
skins) so the odd dodgy potato may be OK but a whole mealful of them
might not be.
3) that it gives a bitter taste to the potato, so don't eat any potato
that tastes strange.

Wikipedia reference is about the most informative in one place:
http://fixedreference.org/en/20040424/wikipedia/Potato

How many gardeners, I wonder, have looked at their potato patch, seen
green tubers poking through the soil, realised they're overdue with
earthing-up and have gone ahead and earthed up with no further worries?
--
Kay
"Do not insult the crocodile until you have crossed the river"