Related to rubystars question...
First, To the question of plucking hair.
ok, here's some info,
The chafetz chaim in the concise book of mitzvot published of course by Feldheim(only the best!)
His book has mitzvot relevant to today(since no temple and no sanhedrin).
He lists negative commandment #179
Negative commandment: That a man should not wear a woman's garment
under that, he says this refers to clothing or ornaments... And that a man should not pluck out white hairs from dark hairs. from his head or beard.
By rabbinical law, a man is not allowed to allowed to remove hair from his armpits or pubic hair. Whoever removes it from a place where generally none by a woman removes it, is violating this and deserves lashes. It is permissable to remove the hair from other areas with a scissors.
So. I guess if you want to go by the general principle, a jewish man shouldn't be plucking hairs because it's an effeminate thing to do. But from a legal standpoint, it's usually permitted, moreso with scissors than plucking.
So
what is clear from that, is you can't pluck white hairs from dark hairs, on the head or beard. And you can't cut even with scissors, pubic hair or armpit hair.
Assuming the translation is right and you trust the words to the letter, it means you can even cut white hairs from dark hairs(but not pluck)!
Thing is though, there is another commandment relevant to hair, to do with not using a razor against the face
Regarding tattoos
Chafetz Chaim lists it as -ve #163 Not tattooed marks in one's flesh.
he quotes
Leviticus 19:28
"Do not lacerate your bodies for the dead, and do not tattoo yourselves. I am the LORD."
A tattoo is an incision which is filled with ink or some "other" colouring..
Note- I don't think any of these things are based on scripture , they are from the oral law, but scripture either hints at them or says them expicitly. It is misleading!
Not so related to tattoos, but the chafetz chaim lists as #28, quoting
Deut 14:1 is not to gash yourself in idol worship.
So I guess if that was the whole story then you're allowed to gash yourself if it isn't idol worship and you don't put ink in!!! Though perhaps that wouldn't be in line with the general principle of not harming yourself..