idioms - Making sense out of Japanese proverbs

I was never able to make any sense out of the following Japanese proverbs or idiomatic expressions:

豆腐の角に頭をぶつけて死んでしまえ。
'Hit your head against a corner of a cake of tofu, and die.'

...の爪の垢を煎じて飲む。
'take extract from one's dirt/wax under the nail, and drink it'

They are nonsense to me, and the latter is also disgusting. How can you die in such a way? What is the purpose of drinking such thing? How can you make a sense out of them?

Answer

豆腐の角に頭をぶつけて死んでしまえ。

Used to say that a person is so stupid (that he would believe this and real find a piece tofu to die). (source)

...の爪の垢を煎じて飲む。

Use the dirt under the nail of ( some expertise ) as a drug, (you'll get some of his talent). (source)

名人の爪の垢を煎じて飲めば少しは腕が上がるだろうに

It'll be hard to make any sense out of them if you see them alone. I'd recommend you to find some reference.