Cosmetic expiration date?

I have some cosmetics that I use, and their expiration date has passed by about 3 to 4 years,
So I'm wondering if it's okay to use it.

I saw that about two-thirds is left!
I think I'll have to use the rest,
The problem is that the expiration date has passed by about 3 to 4 years.
If I want to use what's left, can I just use it?
Or should I just throw it away?

source: Concerns here