Valve Cover Gasket

[Kneale Brownson]

I'm doing my first ever valve cover gasket replacement.  

The old gasket was stiff as though made from hard plastic.  It came off
both the cover and the spark plug holes in hard chunks I had to pry off.
Before I did that, I determined there were two cracks around spark plug
holes and two along the passenger side of the cover, where it had been leaking.

Anyway, is it normal for the really soft and flexible gasket (judging from
the replacement one) to get so dry and hard?

And what's the best way to get the oil out of the spark plug holes?